Rob and Big: Too bromantic.
Catherine and Heathcliff: Too long. Too boring.
Calvin and Hobbes: Too furry.
The kids from Bridge to Terabithia: Love interest died during filming.
Oedipus and Mom: Oedipus didn’t want them to air it. He felt he was blind-sided at the end of the episode. The producers agreed; the end was unsightly.
Kanye West and himself: It was clear from the get-go that they were already much more than friends.