One thing that I think almost every religion on the planet has in common is that somewhere in their teachings is some form of Karma. No matter how it is worded there is some mention of the fact that how your actions others is how they will come back to effect you in some way.
It's basically the principal of cause and effect. A perfectly wonderful idea if you ask me and one that I wish some people would get through their thick skulls. If you act like a total douchbag the universe is going to respond in turn. Duh! Now, I am not saying that it is easy to live by the idea of do onto others as you would have them do onto you. ( I know I can't do it as people suck and I have a nasty temper)
The general concept is what I like though, the idea that if you put enough positive energy out into the world it will come back to you. It's enough to keep me going some days, the idea that it will hopefully get better. That's not why I'm generally a good person. I try to be the person I would like my children to be when I am not around to scare them into behaving. (after all monkey see, monkey do) This is not always achieved because I only human but I try my best. (because if I every catch them acting like one of those horrible teens I see out in public now I will go to jail)
That being human is also part of what drives me to be a good person though, I go after the man on the subway who dropped his wallet on the seat because I know how much it sucks to have to replace all your crap. I hold the door for the person behind me because it just makes sense, I give the pregnant lady/small kid/old woman my seat on the bus because it's polite. Plus standing on the bus pregnant sucks.
Plus something I learned when I was like 5, if you are nice to people they will give you cookies. (true story, Karma in action)