It's rude to tell someone you hate them.
Timmy and Suzy are school friends and are playing together, but are fighting over who gets to play with a toy.
Timmy wants to play with the toy.
Timmy compromises with Suzy by letting her play with the toy for a few minutes.
Timmy grabs the toy and tells Suzy he hates her for trying to take it.
Suzy plays with the toy, then Timmy gets to play with it.
Suzy cries and leaves, and they never play together again.