A guy is standing on the corner of the street smoking one cigarette after another.

A lady walking by notices him and says
"Hey, don't you know that those things can kill you? I mean, didn't you see the giant warning on the box?"

"That's OK" says the guy, puffing casually "I'm a computer programmer."

"So? What's that got to do with anything?"

"We don't care about warnings. We only care about errors".