To be honest I'm not sure why everyone likes her to much. She doe shave that mystery factor. Apparently some people like that a lot, though I personally don't because mystery can easily lead to horror. I also find it disturbing that so many people want to have sex with someone when they haven't even seen their face.
In the first game Tali had very little personality. She was basically a blank slate, mostly used by the writers to expand on the backstory of the Geth and Quarians. Though because she had so little personality there wasn't anything there to really hate. In the second game they apparently expand on her personality, but so far I haven't seen it. All she has done is whine about either Cerberus, her home world, Legion, or the Geth in general. At this point it's easy for me to just dismiss her as a whiny racist *****.
I would try talking to her more, but she is stuck in a perpetual funk because I sided with Legion instead of her. And I can't talk to her with my male Shepard because then I risk falling into the romance trap.