If stuff never goes as quickly, then you should know that, and not book people in.

I find it a statement that my time is far less important than the Dr's time. I am expected to be there on time, and then wait an hour or two for a 15-minute appointment.

Lead-in -- that doesn't grate nearly as much. Hopefully it means someone is trying to manage their load. Of course, they don't need to be impolite to you about it.