Joke

I was sitting in the foyer of a bank when a young man walked by and then stopped for a moment on his way out. I noticed that one of the latches on his overstuffed briefcase was unfastened, putting strain on the remaining latch.

"You're going to lose the contents of your briefcase," I warned him.

Just then the case burst open. He stared at me with something akin to fear in his eyes as he gasped, "How on earth did you do that?"