A man walks along, and sees an old man sitting on a park bench. The old man is perhaps eighty, and is crying his eyes out.
The first man approaches the elderly one and asks "What's wrong?"
The elderly fellow replies. "I just married a twenty-year old girl, and..."
The first man prods him: "And? Do you have troubles with..."
"Oh, no, no. I have incredible stamina for a man my age, and we make love twenty-three times a day."
The first man, obviously surprised, asks "So what's wrong?"
"I forgot where I live!" bawls the old man.