I was playing as Michael after the 'predator' mission and I went over to Trevor's trailer to see if he was there. Ron was on the porch, mumbling about paranormal activity, and when I pressed the right directional button, Michael said, "Well, if it isn't Trevor's even weirder friend!" and "You know, you're pretty creepy!"
I killed him with a grenade, just to see if I could, which imediately got me a two star wanted level. A scream came from inside the trailer, and when Trevor noticed Ron's flaming corpse in the doorway, he completely freaked out and started running back and forth in a panic. The cops arrived at this point, and he ran out the door. I stayed in the trailer and blew away any officer who dared to enter. As all of this was going on, Patricia was calmly cleaning the counter. When I aimed my gun at her, she said, "No. You no point that at me."
Other things I've done that would qualify include running over Lamar about ten times, backing up and then pinning him between the hood of Franklin's car and a brick wall only to have him get up again, firing rocket launchers around the town, blowing up Amanda with a rocket launcher, etc. I also had Michael deliberatly shoot up his own house, destroying chairs, tables, vases and other things.
Additionally, I was recently playing as Trevor, and I took Wade down to the pier. I decided to start fighting with NPCs just for sh*ts and giggles, and before I knew it, there was a group of pissed off NPCs who wanted to beat me up. Wade said, "Don't hurt me! I don't like being hit!" but then he temporarily dropped his sweet and friendly personality and when berzerk on the NPCs. He gave a couple of guys the Johnny K treatment.