I am male and have received the "you don't look like a programmer" comment on numerous occasions. It usually comes from other men, so it's not typically followed by the "are you single?" question. Is it the latter that makes you uncomfortable? To be brutally honest, I find that kind of question rather flattering.

Another one I frequently hear: I farm as a hobby. When I meet someone and talk about my farming adventures first, then tell them I also develop software, they are always like "Whoa, you know how to program computers? But you are a farmer!" like a farmer isn't smart enough to do that kind of work. Personally, I think it is funny knowing that farming is the one that is far more mentally challenging out of the two, but it really could be hurtful if directed at the wrong person.