Hi Lizzi! Very few, really. Once in a while there’s someone who means well but who’s totally oblivious to social cues. Or someone who forgets that my singing in his/her headphones does not mean that we know each other in person, at all.
Fun rule of thumb: the ones who say "Sorry, you must think I’m such a creepy stalker" tend to be some of the least presumptuous, most thoughtful people we get to meet after shows.