I was guest-DMing. After 1 person hilariously failed a challenge that another player came up with a completely different solution, they were presented with a thick stone door. On the door was 5 markers. On each marker was a different symbol...a flame, a bolt of lightning, a snowflake, skull and another I cant recall maybe a star.
The person who hilariously failed the first challenge kept trying to push the markers with their bare hands, and each time I said "nothing happened", so she tried a different one, tried pushing it harder, tried pushing 2 at a time, tried hitting it with her weapon, which I asked if it was magical and she said so, then kept trying the same thing over and over again. She kept talking over everyone and I even think she said "this puzzle is stupid". I was seconds from scream "look at the symbols" when someone took a swing at it with their radiant sword that things started clicking into place in their heads. The dumb one then tried using a level 2 fire spell and I think let out an audible groan.
In advance I made sure all players had cantrips of these particular damage types while building this puzzle and she wants to use a level 2 spell. For reference she's an OP druid (because she cheats on all her rolls), has a higher AC than our barbarian and more HP than our paladin, yet considers herself "squishy" and stays in the back peaking out behind cover to shoot with a crossbow, and takes it as a personal attack that everyone hates her if any enemy does damage to her.