If somebody falls into a trap, that's one thing.
I've often thought of saying, "Oh, crap," or "I hung my queen," but I would never do that because it just seems too silly.
Blunder? Naw.
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Arstan wrote
I've often thought of saying, "Oh, crap," or "I hung my queen," but I would never do that because it just seems too fishy.
Agreed, would stink. 
I recently completed a game that required a bit of bluffing to get the job done. including a 'Doh...' after I did the move. On the surface it looked like a blunder, but deep deep down, a trapdoor awaited.