Barking Up the Wrong Tree

A wizened gentleman is sitting on his front porch when up walks a young man with a clipboard in his hand.

The porch-sitter asks: "What are you selling?"

"I'm not selling anything," the young man says. "I'm the census taker."

"A what?" the man asks.

"A census taker. We are trying to find out how many people are in the United States."

"Well," the man answers. "You're wasting your time with me, I haven't the foggiest idea."