God, the stuff I've done. Blowing up Megaton JUST to kill that goddamn annoying voiced trader woman was one, but.. oh, she survived, dammit.
Any numerous millions of times I've played around with corpses and limbs; I think I have a gif somewhere of two corpses in Oblivion doing the horizontal bop via that handy "grab but dont take" key. I've stolen every single coffee cup I can find in the game, the grand total so far is around 500-600. They ain't getting their coffee.
That was purely due to the games similarity to Oblivion though, I used to steal forks back in TES days.
I became so annoyed by the unkillable children that I spent several minutes firing mini-nukes at them and generally trying to set them on fire, well, there's probably more but it's late and I've forgotten.
Oh, a good unintentional one. I shot a raider in the head in a valley, and as I was reloading and looking around for more, I saw something streak violently through the air. As I watched, I realised the raider must have hit a stress point in the map or something, he was getting thrown violently around this valley. About ten seconds later he hit a cliff. Very hard. The limbs could have been found half the world away, I shit you not.