Probably laughing maniacally while mowing down animals and pedestrians on Carmageddon, or nuking the crap out of everyone on Civilization II. XD I'm oldschool like that. Also, on Rise of the Triad (another oldschool PC game!), there's this one enemy where if you shoot him a certain number of times, he'll drop to his knees and beg for his life. Naturally, I'd try doing that every chance I got.
In Skyrim, when I was heading to get my dragon breath ability, I met an Ice troll and ran away. There was this praying lady at this stone thing. And I led the creature to her. It killed her and I took care of it after. I didn't technically kill the NPC, so I didn't have any problems taking her equipment. She had Dragon Scale Armor. I wasn't going to restart the game so she would live. I liked her stuff. It's still funny hearing a town guard mentioning I have nice armor, but he can't prove I killed a character in the game because of the Ice troll.