One false move, very costly move.

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A friend gave me a present from abroad. It's a nice cd player with radio and subwoofer. He said he tested it already and he's sure I will enjoy it. I was so excited and plugged it right away, I can't wait to hear a beautiful, heart pounding subwoofer sound. But instead of a beautiful sound, smoke came out. The power was set to a 110V mains supply, I should have set it to 220V first. I always check out things like this but in that particular case, I didn't. Do you have any similar costly false moves?