I did a bad thing in a game once and I thought about it for a long time.
I was a corporate fixer for Gazprom in an alternate version of Liverpool run by the Militant. There was a girl working for an escort agency and my bosses told me that there would be a significant payoff if we delivered her. We were told she was involved in espionage. Which we believed to be the case.
I and some friends carefully planned the perfect abduction and carried it out. It took two or three sessions, so six to nine hours of my life were spent committing this imaginary crime.
In all the schemes our Cyberpunk characters had tried, this is the only one that went off perfectly. Its also the only one that was really very very immoral in an immediate sense.
All of the things we did were somewhat dodgy, we tried smuggling drugs, we got into gunfights with priests and went gambling. At one point my character had a security guy tied up in a basement and executed him in cold blood. He also betrayed numerous friends, including real people who were right there at the table in front of me.
But I never went home and thought about it much afterwards. It was only the imaginary girl. We did it without thinking about it. Only later, lying in bed in the dark did I start to wonder if I did a bad thing.
I decided that I was going to play my character as a fractured good guy from that point, which I failed to do, and he decided to rip off some gamblers, which he failed to do. He was shot by police. Which he deserved.
Maybe it's because it was a woman, or because we never really knew why they wanted her, or because we only met her once so she didn't really have any personality, she was just a cipher really. A blank space to read into.
I was reading a Zak S post on G+ and thinking about morality in games and if the things in games have any relation to the real world. I think they do, but the translation between the two is long, distant, inconstant and strange.
I imaging holding a long loop of very pure silk in my hands, it's evening and the silk is grey so it just reaches off into the gloom, you don't really see any particular point where it disappears, only endless fine gradations of darkness. And the silk is being pulled through my hands, sometimes fast, sometimes slow. It's so smooth that I can barely tell its moving at all. I have to concentrate on the sensation in my fingertips but I can never be certain. I could clamp down at any point and the silk would be still, but I don't.
I banned rape in my D&D games. And child abuse, and child endangerment. It's never actually come up with anyone I play with, so it's only a tacit rule, invisible and untested. But it's there.
The murders and thefts go ahead as normal, they don't leave any particular stain on my memory. I don't think about them while I walk home or before I fall asleep.