It's probably my worst pet peeve when people misrepresent something. I'm all for deceit, lying, whatever, but I hate when someone misinterprets something you say or do and pass judgment based on it. Or if someone gets / doesn't get credit for something for the wrong reason.
This came up most recently today when someone started a conversation that somehow switched to his sex life. He talked about being a virgin and basically came off as retarded and super homophobic. I was definitely trying to dash all his beliefs, but was pretty simply saying "look, I know vagina is super awesome, and in all likeliness you'll love it to death. Until you've experienced that, penis, or both though, you wont really know if you're 100% straight." To which he replied "God, what's with you fags always trying to convert straight guys?" and stormed off. Now, I wasn't offended because he called me gay, nor because he decided he didn't like me or my beliefs, I didn't really care. I hated the idea though that he was completely missing my point and basing his decision to end the conversation on it.
It ended with me yelling up a stairway packed with 50+ people "you get back here and hate me for the right reasons!"
It wasn't a high point.