I don't know why some of you are hating on Bianca. All she is is a walking disaster who hasn't a clue about the ins & outs of Pokémon training. She's a good enough person outside of her lack of dexterity.
To sum it up, Paul would take my vote as the biggest jerk that I've ever seen. I mean really, he looks down on other trainers who doesn't see to his exact method of training & raising Pokémon. Thank god Ash rose to the challenge when he needed to the most.
Other rivals that would qualify as jerks in my book would both be Burgundy & Georgia. Burgundy is an arrogant connoisseuss who always snipes at a trainer's Pokémon of its flaws, rather than giving them praises & advice. To add insult to injury, she can't even do this sort of thing, as she is a lowly C-class.
For Georgia, she pretty much is someone who gloats about her adventures of dragon busting, & thus thinks that she is all that. That's bad company in my book.
Both of these two are a term which I won't mention here. If one is bold enough to know what that term is, they can PM (not VM) me.