When I was a teenager, my dad would get frustrated and make various empty threats. We grew tired of this. One time, while working on his car, he stomped in to announce he was going to throw a match in the gas tank. I told him to wait, and came back a few minutes later with a pair of plastic 35mm film canisters. I explained "pour the contents of one into the other, shake, and snap on the lid. Drop it in the gas tank and get away. You'll have about thirty seconds."
My dad was horrified. However, he never made that particular threat again when I was around.