A long, long, time ago, when I was 19 or 20, I went to a bar with an older friend. The guy at the door asked for my ID. I gave him my driver's license, which of course had my date of birth printed on it.

He looked at it and said, "You have to be 21 to get in here." I replied, "That ID is a few years old."

He looked at it again for a moment, then said "Oh, OK" and let me in.