Psyringe: Indeed, for GTA4, the "being a gangster", and the cruel, violent and inhumane actions that the game forced me to perform, were one of the reasons why I just couldn't tolerate playing it beyond the first chapter.
Jonni: I used to have the same problem with playing evil characters in RPGs when I was younger. Just couldn't bring myself to choose the "evil" options.
Eventually I realized that they're just games and picking the evil way in a game does not carry over to real life.
I actually have no problem playing "evil" characters in fantasy settings, or in settings that offer you a choice. In Skyrim my "evil" bosmer thief/assassin was arguably more fun than my "heroic" altmer mage. I play many games with "evil" characters and enjoy them. However, GTA4 is a special case in several regards:
1. Its setting clearly tries to mimick the real, nowaday world, so it has a much stronger connection to real life than a fantasy, scifi, or even historical scenarios, to the point that I can't brush it off anymore with the "It's just a game" notion.
2. Despite being touted as an open world game, it offers you very little choice with regard to your actions. In one side mission, you have to shoot an unarmed passive man in the knee just to make a point of a threat. You have no choice about this - you cannot choose to give a warning shot, or to resolve the situation (which has your ally in full control, mind you, there's no threat _to you_ at all) by any other means. You can't even use fists. You can't even leave the situation. The game simply instructs on the screen "Shoot the man in the knee", and you have to do exactly what the game says and incapacitate this man's leg for weeks, just because the game forces you to make a particular point in one particular way.
In another scene, the game forces you to execute another unarmed, passive man, after he's already given up, by putting a gun to his eye and pulling the trigger. You are then "rewarded" by a slow motion cutscene which shows the blood bursting out of the victim's head. This scene is mandatory, you have no choice about it - if you want to progress in the game, you have to play it out in exactly this way. The game tries to give some justification for this cruel and violent murder by painting the victim as an "evil" man who "wouldn't stop harrassing" the main character's cousin, but you can see how such a "justification" is pretty problematic in a game that forces you to commit similarly evil deeds yourself, right?
3. The game not only forces you to commit rather heinous acts, it also permanently demonstrates you that these acts have no negative consequences whatsoever. Crash other people's cars? The police won't even take notice unless you hit their own cars. Mow down pedestrians with your vehicle? Drive 2 minutes out of range of the police, and all is forgotten. Kill harmless, defenseless walkers on the open street? Same, just spend a minute outside of the police's immediate reach.
Taken together, all this has a message painted all over the game that I just can't tolerate while playing. If other people can, that's fine, I certainly won't tell them which games to (not) enjoy, and certainly won't blame them for enjoying something that I can't and really don't want to enjoy. But nothing of that changes the fact I find that particular game disgusting, due to the reasons listed above.
Anyway. That's probably, for this thread, a way too detailed discussion that's even off-topic since GTA4 is not even on sale. It's just that GTA4 in particular gives me the urge to step on my soapbox. But I'm finished now, move along. ;)