The July 2008 edition of Dean Sluyter's Questions column provides two answers to the old standby "How can I get enlightened?" The first answer has one graf I particularly liked:
The Eightfold Path is not a program of accumulating merit (or merit badges) so that someday the Big Buddha in the Sky will open the gates of nirvana to you. Yes, some of the old texts can make it sound that way, but today sophisticated Buddhists generally give that language a more inward and immediate application. ... [I]t's pretty hard for most people to get their minds quiet and clear enough to recognize [that nirvana is right here in the ordinary world of samsara] if they're busy killing or stealing or coveting their neighbors' wives. Virtue is its own reward. ... [I]t helps release your consciousness from complicated patterns of aggression and consequences so that it's free to recognize its own inherent heavenliness. [Emphasis mine.]
We've all heard that one before: "virtue is its own reward." So much so, I suspect, that it's been drained of meaning and has no more real weight than a PSA about seatbelts. But reading that article helped click it into place, and allowed me to put into words a good deal of what has been floating around in my head on the subject for ages.
Most of us are probably familiar with the gamut of arguments about altruism — whether or not there is such a thing as a truly selfless act, etc. My take is that there probably isn't, but it doesn't matter — that there is a threshold of selflessness for a given act that once crossed makes it effectively selfless as far as others are concerned. A friend of mine once put it this way: "Yes, it is selfish of me to do good things for other people, because I enjoy watching them smile and be happy. That is very selfish of me!"
The more you do the right thing, the easier it becomes to cross that threshold without making yourself feel uncomfortable, because over time you lean more towards your desires and everyone else's being in sync. There will always be some level of conflict between what you want and what everyone else wants. You can't get rid of them entirely, but you can lean towards harmonizing them as much as possible. Even if that form of harmony consists of avoiding something entirely, it's better than inspiring further conflict with it.
The other part of how virtue winds up being its own reward is hinted at in the above excerpt. By doing the right thing, you're forced less and less to extricate yourself from the aftermath of having done the wrong thing. I'm reminded of people I used to know who would dream up huge, elaborate and quite physically and mentally tiring plans to defraud other people so they wouldn't have to work a straight job — and yet somehow never realized that it would probably be less work overall just to get and hold down a straight job. (Although, obviously, a lot less exciting — but again, their idea of "exciting" just sounds like unending hassle to me.)
This has implications on both the outside and the inside. When you're not making trouble for yourself outwardly, it's easier to learn how to not make trouble for yourself inwardly. I'm again reminded of people I knew who would encounter something negative in their daily lives, and then compulsively reinforce the badness by venting about it with others: "Look! This bad thing happened! Doesn't it suck? Don't you feel bad for me? Come on, let's commiserate about this terrible thing. — No! I don't want to hear about the fact that you had fun today. Nobody else deserves to have fun when I'm suffering like this." It's hard for me to see this serving any other function than to convince yourself that you're going to be miserable no matter what.
Virtue is its own reward because it makes the inside of your head a much more livable place. And at the end of the day, when your eyes are closed and your head's hitting the pillow, where else is there left to go?