There is a whole array of questions that hoary--and trustworthy--wisdom says you shouldn't answer honestly. ("How do you like my haircut?" "Is Santa Claus real?" "Do I look fat?"). The consequences of transgressing these lines are well-known enough not to need spelling out. But intrepid experiential reporter A.J. Jacobs--who spent a year living in literal accordance with every rule in the Bible--sees need to test it again. So he undertakes a "Radical Honesty" program that requires him, among other things, to tell his wife he often calls her by his sister's name, and to tell an editor he had attempted to look down her shirt.
As you might expect, at the end of the journey he returns to a regime of mild lying. At the end of the program, he tells the news to Brad Blanton, the guru of "Radical Honesty":
"I'm finishing my experiment," I say.
"You going to start lying again?" he asks.
"Oh, shit. It didn't work."
"But I'm going to lie less than I did before."
The long piece is worth a read; the story is great, through the conclusions won't surprise you.