People who slam religion, yet never took the time to actually study it apart from all the rumors they hear from propaganda and those who have to constantly press the issue when one never existed in the first place.
I hate when people do that, along with when anyone zealously bashes anything out of utter ignorance. Examples: A number of heavy gamers, those nut-jobs at the town hall meetings, those types. I don't hate the people, I just hate their ignorance and denial.
If you don't understand something or don't agree with someone, then don't flip out unless you have a good rebuttal. Cripe.