My old DM was a bastard that tried to punish me by limiting my choice to a Halfling Bard, thinking it was a shit character and would die fast. I had some contacts and used them to craft the most kick-arse min-maxed PC one could conceive of, with a rank here, a rank there, all designed to maximise power.
The DM had me split from the party and confronted by the Big Bad. I was more or less done with his bullshit, so decided to kamikaze the bastard.
My said my PC would run up some logs in a logging camp, cast True Strike, cast some spell that increases damage output, leap off of the pile with dual swords drawn, and stab the BBEG.
DM said I could, if I rolled to Cast, Climb, Leap, Attack, and won Initiative - all with disadvantage. I rolled 3 natural 20s and 2 rolls at 18 or 19, and managed to do such damage that I killed the BBEG in one hit.
DM said he teleported away before he died and kicked me out of the group shortly after.
Super unfortunate. Our current DM is pretty amazing. It's a very different kind of D&D world, not steeped in any particularly deep lore or limitations in terms of playing out of character. It's a good experience.