Do I Know You from Somewhere?

A guy is at the supermarket when he notices that the rather good looking blonde behind him has just raised her hand and smiled hello to him.

He is rather taken back that such a looker would be waving to him, and although familiar, he can't place where he might know her from, so he says, "Sorry, but do I know you?"

She replies, "I may be mistaken, but I think you might be the father of one of my children."

His mind shoots back to the one and only time he has been unfaithful. Suddenly he has a revelation. "Wow!" he says. "Are you that stripper from my stag party that I screwed on the pool table in front of all my buddies while your friend whipped me with a riding crop?!"

"Uh, no," she replies. "I'm your son's kindergarten teacher."