Well people should base their opinions on you based on your personality. I find that if a person bases their opinion of you on anything else, that would be prejudiced. What else is there to base off of?
The people I don't like have a personality hat I don't like. It's not that I don't like how they look, it's not that I don't like the faith or opinions, it's that I don't like their behavior and general persona. Maybe I didn't understand the OP, but I find nothing with disliking people based on their personality. I feel that a persons personality is what you should base your opinions off of more than anything.
EDIT: If this thread is about people disliking you for your perceived personality and not getting to know you before judging what your actual personality is like, then I agree with everyone else that it's prejudiced, douchy, stupid, etc.