For Me…..it totally depends on the relationship I have with the doctor or dentists. None of my doctors or dentists would realize who I am outside of their office, so I would say nothing. My podiatrist is a doctor I’m seeing more and more often, so this may change, and if I saw him out with his family, and we were in close proximity to each other, I’d definitely say “Hi”, but I wouldn’t monopolize his time. If he kept the conversation going then that’s ok, but if not, that’s ok too