I had a group of players who were literally ALL new to D&D. Super eager to learn and loves to play. And they do things that NO VETERAN PLAYER WOULD EVER consider doing.
I was running Waterdeep: Dragon Heist, and they are just starting. They deal with the bar right easily enough, and the troll/stirges come out of the entrance to Undermountain.
For those unaware, the troll is kind of underpowered, starting with 6 stirges on it, who fly off back into Undermountain the next round, and who only starts with 44 hp.
Anyhow, I have described these things to the players. One of the fighters literally decides to grapple the TROLL! I can’t make this up!

The best part?! He maintains the grapple the entire fight! Avrae dice were with him on that ONE thing. Then, another player gets the idea to take one of the lit oil lamps on the table, and break it on his sword to make his sword flaming and thereby hit the troll and keep it from regenerating.
I am geeking out at this point. I’ve played for YEARS and have NEVER seen anything like this. Ever.
Their last bit of strategy? While the troll is unable to regenerate one round, to YEET IT INTO THE PORTAL TO UNDERMOUNTAIN!! They try for a couple of rounds, Avrae being fickle. But they do it. They actually do it.

It was so awesome…