A boy was upstairs playing computer games when his granddad came in the room and sat down on the bed.
"What are you doing?" asks granddad. "You're eighteen years old: you’re wasting your life! When I was eighteen I went to Paris; I went to the Moulin Rouge, drank all night, felt up one of the dancers on stage, punched the barman and smashed all the glasses, then left without paying. Now that’s how to have a good time."
A month or two later, the grandfather comes to visit again. He finds the boy still in his room, but with a broken arm in plaster, two black eyes and all his front teeth missing.
"What happened?" he asked.
"I did what you did!” replied the boy. “I went to the Moulin Rouge, drank all night, felt up one of the dancers on stage, punched the barman and smashed all the glasses. But, when I tried to leave without paying I got the <deleted> beaten out of me!"
"Huh,” replied the granddad, scratching his chin thoughtfully. "Who did you go with?"
"Just some friends. Why, who did you go with?"
"The SS."