Damn things kept going off in my pocket.
Edward G. Robinson as Barton Keyes in Billy Wilder's Double Indemnity -- talking about why he doesn't carry matches any more.
At least that's what I think he said. That's how I remember it, and it comes to mind every time something or someone explodes on me without warning.
But I can't confirm it with an online reference, and it's been years since I saw the movie, so it's entirely possible that I got the whole thing wrong.
Wouldn't be the first time.