Writers know what it is, and readers do, too: Too Dumb To Live. It's that moment in a book where a character does something so out of logical bounds that we're thrown out of the story while we scream (silently, one hopes) "No sane person would go into that basement/warehouse/alley/crypt, etc. In the book I'm reading, it is the hull of a ship that's aground in the Arctic Circle. The two men (Double TDTL) rappel into the hold in their street clothes, knowing that a) the ship is sliding off the shelf and will soon sink, b) there are unexploded charges aboard, c) the water temperature will kill them in minutes. Maybe understandable if they had to save the President or find the Holy Grail or retrieve Mom's oatmeal cookie recipe, but no - they're pretty much just looking around.
Writers know it has to happen sometimes, but readers really need at least one sentence that gives it credence. "Hank, you're always been a crazy bastard, but you're my friend, and I'm not letting you do this alone." Or "Hank knew it was crazy, but the need to find out what was in that hold was overpowering."
Come on, guys. Help a reader out.