Not just looking into people's mouths, but half of your clients are terrified of you (far more than any other profession) and you have to cajole them. You will also be causing pain to people in the course of your job (can get minimal, but there will always be some), which some clients really can't handle. I imagine you get used to the smell of drill-burnt rotten teeth eventually, but the terrified people... I don't know how they do it.
