I am curious how is Zara unbearable and Bella not ? Bella is a full out bitch, Zara made a dumb mistake and has apologise for it.
Man I've addressed this so many times. In short, to me, characters like Bella and Vanessa put up a bitchy front but immediately fold when called out. They are transparent that way. They are aware of the façade they put up. And what you see beyond that façade is pleasant to me. Gives a healthy and nice balance to the character.
Then there are characters like Zara and Nia. Damaged goods with so little self awareness. They aren't putting up a façade, they're just unbearable. To listen to. To watch. To be around. I just want out whenever they're on the screen. Zara's "competitiveness" drives me up a wall. Poorly handled mommy issues reeking of insecurity, manifesting themselves in the worst way...arrogance. I don't want to even play that game with her.
Trust me I'd be harder on Vic too if she hadn't had the accident. Too much sweetness and naiveté can become harder to stomach later on.
EDIT: To be clearer: what I despise most about Zara is the fact that all her sense of self worth seems to be tied to "winning". I can't take it. And I don't know how else to put this in a way anyone who likes her can understand my perspective.