"When I was young," an elderly gentleman reminisces, "I was  a mime."

"Really?" his grandson says.

"Sure," he says. "I could mime the act of pulling a rope, and people would think I was pulling a rope. I could pretend I was a bird, and people would think I was flying."

"Did you pretend that you were trapped in a box?"

"No," he says, "I would never do that."

"Why not?" the grandson asks.

"Because," he replies, "I'm claustrophobic."