I'm reminded of a time when I was DMing years ago and the players were in a dungeon that was set up by Wizards Of The Coast and not me. Anyway, there was a rogue in the party that checked EVERYTHING for traps. I'm talking not just every threshold, but he was checking mounted torches, walking and examining every wall stone by stone. So the party grills him for slowing the game down so much. Well, the next threshold he just walks through and friggin explodes. The damage was triple his max HP and he was LIVID! I took the map out while I was laughing, everyone else was frozen open mouth shock, and showed them I didn't make it up on the spot. I felt so bad afterward I revived him as an undead Reaver needing vengeance against traps.
-Adventure League DM