A man arrived at a walk-in medical clinic, promptly at opening time, only to find two other men outside, waiting.
The door was still locked.
He knew one of the men and they started talking. About five minutes later the receptionist came running across the parking lot, apologizing for being late.
The man turned to his friend and asked, "Are you first in line to see the doctor?"
"Yes," the other replied.
"Well, I guess I'm third then," he said.
"No," the second man said, "you're second."
"Second? What about you?"
"I'm the doctor."