My dentst: I don't want to call you Martin, I want to be scared of you, keep you at a distance and call you Mr W***. Your false friendliness sounds just that. Just look at my teeth, tell me the good/bad news and let me get out of there a.s.a.p., please.
On the other hand, you are a good dentist practicality-wise, so I'll put up with you.
Oh, and enter the 21st century and start accepting card payments. Nobody uses cheques these days for such things. Unless you're called Rees-Mogg, of course.