I started GMing a Edge of Empire Campaign a couple of months ago. We've had only a handful of sessions so far. I started with Escape from Mos Shuuta, then Long arm of the Hutt, and ran them through the start of a semi-homemade adventure on Tuesday night. In the session I faced them off against a slaver who had a bounty on his head, he was also the slaver that sold two of the PC's into slavery to Teemo. The bounty was for 5000 alive, 10000 dead.
By the end of the adventure they confronted him as he prepared to load new slaves into his ship. After the battle the slaver was captured alive. The player playing the Wookie, who was the bounty hunter, killed the slaver after they got some important information out of him. The player explained that he was going against the Bounty hunter code: that if a bounty is captured alive bounty hunters are obligated to keep them that way until the bounty is turned in. His character has a motivation to free slaves because he used to be one. He felt that the fact that the Slaver enslaved him and was currently enslaving a group of others that he felt compelled to end his life, even if it meant breaking the Bounty Hunter creed as well. He wasn't going to let him live.
To me that was awesome, because the player was really playing the PC's character. He gave it thought and felt engaged enough to mention it. He gave some thought to how his PC should act. It was really awesome to see. It's moments like this that makes me really enjoy RPG's.