I was in a campaign with two other players. We got into a boss fight.
My character very rapidly ended up on 0 HP and was rolling death saves the entire time (I was stabilised, then damaged, then ended up so my character's life depended on one roll. It was a nat 20 so I managed to sit up right after combat ended).
One of the other players had managed to get on the boss's good side before we started, and then did nothing the entire fight. Annoying.
The last player then had to fight the boss entirely alone. Somehow, they pulled it off, while managing to stabilise my character at one point. I was very impressed.
Edit: I forgot to mention that in the one turn my character did take, they managed to deal two thirds of all the damage in the entire game. They weren't even a spellcaster.