Being 5-10 min late is pretty typical for most doctors I've seen. If it annoys you, remember that they're probably late because they are helping another patient. Hopefully when you're having a really bad time, they'll give you a few extra minutes too.

I can understand how frustrating it can be for them to be late though. I always have anxiety before my appointments, and the sooner I can see the doc, the sooner I can calm down.