I have a hard time being a bad guy in games. In Civilization games I'm a peace monger, in WRPGs I'm chaotic good, in JRPGs I don't have any other option. I still play bad guys sometimes, but I always feel a tug of guilt when I do something hurtful.
Some games are smart enough to punish me for this quirk.
In Fallout 2 your travels eventually take you to a pair of neighboring cities. They are Vault City and Gecko.
Vault City has the nice veneer of a modern, first world nation. It is clean, wealthy and even has a stable government in place. Unfortunately its government is somewhat totalitarian, the lower class are horribly mistreated and many people are held in a "polite" form of slavery.
Gecko looks like a ran down shanty town with a massive nuclear plant in the center of it. It is inhabited by mutants (AKA Ghouls) and just screams desolate. Fortunately it is ran by wise and decent heads of the community and the people are relatively friendly.
When you reach Vault City, the "First Citizen" wants you to eradicate the inhabitants of Gecko and destroy their plant in order to stop them from irradiating Vault Cities water source. The people of Gecko do not want you to do that.
If your character is somewhat intelligent, persuasive and/or has a shred of decency you can find a better solution. I worked out a deal between Vault City and Gecko that lead to Gecko taking more care with their ecological footprint (Not a term that gets used much in a nuclear wasteland) and Vault City will begin trading medicine with the citizens of Gecko.
I felt warm and fuzzy, got yelled at by the First Citizen and went on my merry way.
After I finally beat the game I was treated to my favorite kind of ending. A modular, town by town, 'make your own' ending. It filled me in on all of the results of my heroic acts. Letting me know that the world was a far better place because of my actions.
Oh, and the fact that the people of Gecko were enslaved when Vault City annexed their city.
I was crushed by that realization.I was doing the right thing. I was a paragon of virtue. I was a loose cannon who played by his own rules and went behind the first citizens back in order to save the day. What the hell happened?
I felt a little older walking away from that play-through. A little wiser. A little less innocent. I look at the world through a darker lens now.
Also I made sure that on my next play-through I murdered every single son of a bitch in the corrupt and evil upper class of Vault City. It may have seemed cold to them at the time, but I had seen the future and they had it comin'.