"It's not logical," he says, with a little smile. How much of human behavior is, really?

"If I had to guess, I'd say it offends some people because getting caught in a lie can make people feel guilty for lying in the first place. Feeling guilty makes people defensive. People get self-righteous, because then they have to question whether they've done something wrong, and they'd rather not think about it."

That's part of it. There are other aspects, too, he thinks. The simple fact that being caught in a lie can have deadly results, for example.