You’re reading a romance novel or one with a major romantic subplot and then the designated love interest of the female (or male) protagonist does something that hurts the protagonist and you hate them for it, and wish they didn’t end up together… but sure, they end up together.
Due to the nature of this discussion, spoilers from the books are included.
Example of how to write:
Gideon de Villiers from The Ruby Red Trilogy.
>!spoiler here!
My answer as well. I hate his guts, not just because he’s a dickhead, but because he is the exact same jealous, selfish, emotionally abusive dickhead at the end of the series that he was when he first appeared. He does not grow at all. Hate, hate, hate him.