The most recent example would be my comment that everyone becoming bisexual might lead to a net social loss, although the karma scores have gone up since that discussion happened (and so maybe I just need to wait before updating on the karma of contrarian comments).

I spent way too long looking through other comments I've made, and only really came across this example. I suspect this was misapplying discontent caused by other arguments. I had already noticed a while back that when I made a sloppy comment it would often get downvoted, although I would be able to make up the karma by explaining myself downthread. The only other significant example I can think of was in a thread about infanticide where I accidentally implied that I could be for the criminalization of abortion, and that comment got kicked down to -3 karma, with +1 karma from my following comments. (It's hard to decide how that whole thread contributes to this question, because the person who said "well, I can't say this many places, but I'm in favor of infanticide" got upvoted to 41 karma. That suggests to me their position isn't contrarian locally, but I suspect it is contrarian globally.)