Forbidden Friendship

A character wants, very badly, to be friends with someone specific. But sadly, the rules of family or society look down upon the friendship, and won't allow it. There's a number of possible reasons for this: If their relationship is or becomes romantic, they may be Star-Crossed Lovers. All of this can be affiliated with Heroic Disapproval.
 * Prejudice. Whether it's class differences, racism, or any other difference, an entire group of people is declared "evil" and must be avoided if one is to be socially accepted.
 * Personal vendetta. Sometimes one family hates another, and won't allow their own to hang out with the other family. Not everyone in the family shares that dislike, however, and they might become friends anyway.
 * Safety. Sometimes the society or family has a fear of a specific individual, whether warranted or not. And who wants to see their friend hanging around someone who might kill them?
 * Bad influence. Sometimes the specific individual isn't so much a threat to the character, as to society's value system. Friends who do drugs, get into trouble, and so on, might be disallowed as company for the main character.

20th Century Fox

 * Ruth Dewitt Bukkater unallows her daughter Rose to be with Jack Dawson.

Don Bluth

 * Mr. Threehorn forbids his daughter Cera from playing with Littlefoot, who is a longneck.
 * Itchy forbids Charlie from befriending Anne Marie, believing that she's causing Charlie to abandon his planned vengeance against Carface.

Illumination

 * Dr. Nefario forbids Gru to officially adopt Margo, Edith, and Agnes, believing that they will distract Gru in his plan to steal the moon.

DreamWorks

 * Hiccup befriends a Night Fury dragon which he names Toothless, despite humans and dragons being natural enemies

Disney/Pixar

 * Kerchak forbids Tarzan from socializing and interacting with the Porters.
 * Stinky Pete, telling Woody against his friendship with Buzz.
 * Big Mama, discouraging Tod from continuing his friendship with Copper, whom she fears might grow up to hunt down the fox, like the hunting hound he is supposed to be.
 * King Triton forbidding his daughter Ariel to have contact with the human world, especially Prince Eric.
 * Judge Claude Frollo forbidding Quasimodo to be friends with Esmeralda, thinking that gypsies "aren't capable of real love."
 * Chief Powhatan forbids his people from befriending the English settlers, who he believes are dangerous.
 * Ratcliffe threatening to hang John Smith for befriending Pocahontas
 * Simba harshly demaning Kiara to stay away from Kovu, believing he was involved in Zira's ambush to kill him, which only result the Circle of Life broken and his late father's goals to not to fulfill.
 * Django unallowing his son Remy to be with the Parisian humans.
 * Mother Gothel telling Rapunzel to stay away from with Flynn Rider, as he's nothing but a common thief.
 * Tod & Copper become best friends despite them being meant to be natural enemies.

Lucasfilm

 * Yoda The Jedi Master forbids Luke Skywalker to put his friendship with Princess Leia and Han Solo before his Jedi Training.
 * Henry Sr. forbids his son Indiana Jones to put his friendship with Marcus Brody before the Holy Grail hunt, which depended on Henry's diary.
 * Tobias Beckett forbids Han Solo to trust Qi'ra.

Others

 * Romeo Montague & Juliet Capulet have a forbidden romance, due to their rivaling families.
 * Rex forbids Babe to talk near Ferdinand as a result of wrecking the living room, while trying to get rid of the alarm clock.

Quotes
"(Anakin: Lower the ship!) I can't take Dooku alone! I need you! If we catch him, we can end this war right now! We have a job to do! (Anakin: I don't care! Put the ship down!) YOU WILL BE EXPELLED FROM THE JEDI ORDER! (Anakin: I CAN'T LEAVE HER!) COME TO YOUR SENSES! (calmly) What do you think Padme would do were she in your position? (Anakin: (pause) She would do her duty.)"

- Obi-Wan Kenobi forbidding Anakin to put his love for Padme before his Jedi tasks

"Isn't this one new? It's awfully good. Looks very much like the Gypsy girl. I know... you helped her ESCAPE! And now, all of Paris is burning, because of YOU! (Quasimodo: She was kind to me, master.) YOU IDIOT! That wasn't kindness! It was cunning! She's a gypsy! Gypsies aren't capable of love! Think, boy! THINK OF YOUR MOTHER! (Frollo takes a moment to recompose himself) But what chance could a poor, misshapen child like you have against her heathen treachery? (pulls a dagger from his robe and stabs the Esmeralda doll with it) Well, never you mind, Quasimodo. She'll be out of our lives soon enough. (he holds the doll over a candle flame) I will free her from her evil spell. (tosses the incinerated doll to the floor) She will torment you no longer. (Quasimodo: What do you mean?) I know where her hideout is. And tomorrow at dawn, I attack with a thousand men."

- Judge Claude Frollo forbidding Quasimodo to be friends with Esmeralda, thinking that gypsies "aren't capable of real love."

"(Kerchak has called Tarzan, Kala, Terk and the other gorillas for an emergency meeting regarding the humans.) EVERYONE! We will avoid the strangers! Do not let them see you and do not seek them out! (Tarzan, actively protesting to the gorilla leader: They mean us no harm, Kerchak!) Tarzan, I don't know that! (Tarzan: Well I do! I've spend time with them!) You may be willing to risk our safety, But I'm not! (Tarzan gets up into Kerchak's face like he's going to fight him.) (Tarzan, defiantly: Why are you threatened by anyone different from you?) (The gorilla leader is stunned by this challenge to his authority and glares at Tarzan.) Protect this family! And stay away from them! (Tarzan sulks off in anger. His mother Kala tries to reason with her son.) (Kala: Tarzan, for once. Listen to Kerchak.) (Tarzan, angrily: Why didn't you tell me there were creatures who looked like me?) (Kala looks on sadly as Tarzan goes to a tree branch to sit alone.)"

- Kerchak forbidding Tarzan from socializing with the Porters.

"Come, Cera. Threehorns never play with Longnecks!"

- Mr. Threehorn forbidding his daughter Cera from befriending and playing with Littlefoot, who is a longneck.

"(Luke Skywalker is packing his X-Wing Fighter to go rescue his friends Han Solo and Princess Leia on Cloud City, but Yoda tries to talk him out of it so he can finish his Jedi Training.) Luke, You must complete the training! (Luke, desperately: I cant get that vision out of my head, they're my friends. I've gotta help them!) You must not go! (Luke: But Han and Leia will die if I don't!)"

- Yoda forbidding Luke Skywalker to put his friendship with Princess Leia and Han Solo before his Jedi Training.

"Walter: Where do you think you're going, young lady? (Lola: Wherever he'll take me.) I forbid you to go out with that hoodlum! (Lola: But Daddy, I love him!) Go to your room! (Lola: I don't even live here anymore!) Well, then, go to your old room that your mother turned into a scrapbooking room! (Lola runs to her former bedroom, crying)"

- Walter Bunny forbidding his daughter Lola to go out with Bugs, who was then a biker.

"Let me give me some advice, assume everyone will betray you and you never be disappointed."

- Tobias Beckett forbidding Han Solo to trust his girlfriend Qi'ra, thinking that she will betray him.

"Bart: I'll come by your house later! (Marge: Oh, no you won't! You stay away from Nelson Muntz.) But, mom! (Marge: Nelson's a troubled, lonely, sad little boy. He needs to be isolated from everyone.) But, mom! (Marge: Yes?) That's all I got."

- Marge Simpson forbidding Bart to go to Nelson Muntz's house.

"Lois: What the hell did you and Bill do last night?! (Peter: We lived, Lois. We lived our lives.) Peter, that former President Clinton is nothing but a bad influence! I forbid you to hang out with him anymore. (Peter: No way. Bill Clinton makes me feel young. Not like you, with your Judd Hirsch sweater and your bag of Werther's Originals.) (Peter walks off)"

- Lois Griffin forbidding Peter to hang out with Bill Clinton.

"Ruth: You are not to see that boy again. Do you understand me? Rose, I forbid it. (Rose: Oh stop it, mother. You'll give yourself a nose bleed.)"

- Ruth Dewitt, unallowing her daughter Rose to be with Jack Dawson

"A cat can't have a rodent for a master. What is this world coming to? It's against the laws of nature!  If word of this gets out, it'll be bad for cats all over."

- Smokey, warning Snowbell against Stuart Little

"This is my land! I make the laws here! And I say anyone who so much as looks at an Indian without killing him on sight, will be tried for treason and hanged!"

- Ratcliffe, forbidding John Smith to fall in love with Pocahontas

"(Woody: HELP! BUZZ! GUYS!)  Stinky Pete: It's too late, Woody.  That silly Buzz Lightweight can't help you.  (Woody: His name is Buzz Lightyear!)  Stinky Pete: Whatever.  I've always hated those upstart space toys."

- Stinky Pete, telling Woody against his friendship with Buzz

"(King Triton shows up in the grotto's entrance, who is very disappointed in his daughter.) (Ariel, shocked: Daddy!) I consider myself a reasonable merman. I set certain rules, and I expect those rules to be obeyed. (Ariel: But Daddy!) Is it true you rescued a human from drowning? (Ariel: Daddy, I had to.) Contact between the human world and the mer-world is strictly forbidden. Ariel, you know that! Everyone knows that! (Ariel: He would have died.) One less human to worry about! (Ariel: You don't even know him.) Know him? I don't have to know him. They're all the same. Spineless, savage, harpooning, fish-eaters, incapable of any feeling. (Ariel: Daddy, I love him!) (She gasps, along with Sebastian. King Triton is shocked and surprised.) No . . . Have you lost your senses completely? He's a human, YOU'RE A MERMAID! (Ariel: I don't care.) So help me Ariel, I am going to get through to you. (He powers up his trident where it glows fiery orange.) And if this is the only way, so be it. (King Triton uses his trident to blast several human treasures, one by one in fury) (Ariel: Daddy!. . . No . . . No, please- Daddy, stop!) (King Triton aims his trident at the statue) (Ariel:. . . Daddy, Nooo!!. . .) (King Triton fires an energy bolt at the statue of Eric, obliterating it. Ariel begins to cry as King Triton calms down before he leaves feeling ashamed for what he's done.) (Sebastian, trying to comfort Ariel: Ariel, I . . .) (Ariel: Just go away.) (Sebastian leaves.)"

- King Triton forbidding his daughter Ariel to have contact with the human world, especially Prince Eric.

"Tod, that Copper is going to come back a hunting dog, a real killer. (Tod: Oh no, not my friend Copper. He won't ever change.) I hope you're right. (Tod: And we'll keep on being friends forever. Right, Big Mama?) Darling, forever is a long, long time, and time has a way of changing things."

- Big Mama, discouraging Tod from continuing his friendship with Copper, whom she fears might grow up to hunt down the fox, like the hunting hound he is supposed to be.

"Now, there's one thing I want to make very plain: no doe of mine is going to be seen with a... a red nosed reindeer."

- Clarice's father, forbidding his daughter to be with Rudolph.

"Love is a distraction. Sorcery requires complete focus."

- Balthazar, forbidding Dave to put his love for Becky before his sorcery training.

"(Stan Marsh wants to spend the holidays with Cartman, but his own family including his mother Sharon disapproves, Also present is his father Randy and his sister Shelly.) The answer is "no", Stanley! (Stan, trying to reason with his mother: But Mom, all the guys are going to Cartman's Grandma's for the weekend!) I'm sorry, Stanley, I can't let you go all the way to Nebraska by yourself. It's the holidays. (Stan: But all the other guys get to go to Cartman's Grandma's; why can't I?) I'll leave it up to your father. (Randy, shrugging: Eh, it's fine with me.) (Sharon ignores him.) The answer is no, Stanley! Now go wash up for supper! (Stan, defiantly: I don't want your lame-ass supper!) (Shelly, disgusted: Ew! You're gonna get it now.) (Sharon is now really angry.) Go to your room, Stanley! Right now!"

- Stan Marsh's family forbids him to spend Christmas with Cartman.

"These white men are dangerous! No one is to go near them!"

- Chief Powhatan forbids his people from interacting with the English settlers, believing them to be dangerous.

"(Fern : But, Dad, I heard them. I heard them talking about the smokehouse!) Mr. Arable : He's not your pig anymore. (Fern : Well, I wouldn't have sold him in the first place if I knew this is what they were gonna do to him.) Mr. Arable : That's what happens to a pig on the farm, Fern. You know that. (Fern : I'll see about that.)"

- Mr. Arable, forbidding his daughter Fern to make Wilbur her pet.

"(Professor: It’s my fault. I put too much value in a material item, instead of the love of you girls.) (Blossom: That’s what drove me to crime.)  (Professor: Oh, Mayor, please…go easy on Blossom. She’s sorry (to her) Aren’t you, honey?) (Blossom: (small voice) Yes.)  (Mayor: What do you say, Chief?It is her first offense.)  Chief: It is very sad. But the law is the law! (Blossom: Oh...)"

- The police chief, forbidding Professor Utonium to spend Father's Day with Blossom, due to her golf club theft.

"(Spike: No-no-no-no-no. The last time I grew up, I turned into a giant greedy monster.) Smolder: Greed-induced bigness. That's totally different. The molt is completely normal. Every dragon goes through it. Pretty soon, you'll leave and strike out on your own. (Spike: Why would I do that?)  Smolder: Have you been living with ponies your whole life?  (Spike: Uh-huh.)  Smolder: Oh. Well, in the Dragon Lands, a molter's loved ones kicks them out at the first stone scale.  (Spike: What? Why?)  Smolder: I think it's biological. We call it the "molt effect". I haven't even told you about the smell.  (Spike: Smell? [sniffs] Ugh!)  Smolder: Yeah. I mean, I love my brother and all, but one whiff, and I was all "See ya!" [sniffs] Speaking of which...  (Spike: Wait! Does the molt effect happen to ponies too? [gasps] Twilight already asked me to leave the castle today. If she kicks me out, where am I gonna live? I'm too young to grow up!) Smolder: I'm sure you'll find a nice hoard of gems to guard or a village to terrorize. Oh, now that dragons and ponies are friends, I guess that's off the table."

- Smolder, thinking Spike's molt effect could endanger his relationship with Twilight Sparkle.

"Mr. Frankenstein: Victor, what have you done? (Victor: You said yourself, if you could bring back Sparky, you would!) Mr. Frankenstein: Yes, but that was different, because we couldn't! It's easy to promise the impossible. What you did was a very serious thing. Crossing the boundary between life and death. Reanimating a corpse! It's very... Upsetting. (Victor: I just wanted my dog back.)"

- Mr. Frankenstein, forbidding his son Victor to bring his dead dog Sparky back to life.

"Male Heavenly Voice: We don't use those old-fashioned names any more. Still, it's me you want to speak to. (Sonny: I've come to get Kira.) Male Heavenly Voice: She's not leaving - it's impossible!  (Male Heavenly Voice, Sonny: [together]  That's what you think!)  (Sonny: How did you know I was going to say that?)  Male Heavenly Voice: Put it this way - I'm a good guesser!"

- Zeus, forbidding Sonny Malone's romance with Kira, though it helped build Xanadu.