Ah my teacher has made comments about my relationship between myself and my boyfriend (we're both consenting adults, but he's older than me) and it irritates me far more than if anyone else said it (conversly, no one else has ever commented negativly about it) because it's unprofessional and innapropriate.
and once I was getting my bloods taken, because I suffered with bulimia and my doctor was concerned about my electrolyte levels, and the nurse said "you look fine to me, I bet you just went on a diet and suddenly your parents think you're bulimic right?" and kept joking about it... I was fuming. If it was me-now and not me-two years ago, there'd be a letter of complaint going to her boss!
Also, (I have loads!) once I was veiwing a university and some students were showing us around (it's their job, they get paid to do it) and she made a totally inappropriate and unprovoked comment about my clothes - basicly insinuating I dressed like a slut, I emailed the university with an offical complaint... (hmm can you tell I'm british? haha)
But yes, inappropriate comments made by people in a professional position irritates me. BUT if they're in a professional position at least you're within your rights to make a complaint.