I've had many discussions with a friend of mine about where the line between enlightened self-interest and greediness ends, and altruism and philanthropy begin.
For example, when I go to church, I'm not going to glory in God or anything. (Sorry, God! I'm certain you know what I'm talking about. I appreciate the whole agape, caritas thing. We'll talk later. 8-]) Religion is way too personal and individual to muck it up with organization and dogma.
I'm going because I like the people there, I often enjoy the minister's little philosophical, slice-of-life homilies, and I think it'll be good for my partner and kid to have the church as a resource for us.
My motivations are certainly self-involved, but they're not negative, and the results are positive.
Similarly, I've increased my community involvement and volunteerism. The reason I'm doing it? Because I want my kid to see this behavior modeled and to learn it as a regular part of life.
I don't have any specific expectations on this one. I mean, I could say our trips to spend time with folks in nursing centers will hopefully mean he'll come visit me if I become old and infirm, but I hadn't even considered that until right this moment. (I hope it'll be true if it comes to that, though!)
The purpose of the King Day of Service is "to strengthen communities, empower individuals, and break down barriers." All of that is very useful to the larger whole, but it also helps the individual.
Service, volunteerism, and charity aren't about others versus yourself. If anything, it's about unity over dualism -- true service helps both the giver and receiver.
Why you do something matters, but a lot of time just the fact of doing it is what's important. What we get out of volunteer activity often exceeds our expectations, and in helping others, we help ourselves in ways we don't necessarily know or expect.
"Just do it" is the slogan of the Nike shoe company, and Nike is the Greek goddess of victory. Participating in the day of service, in any capacity, for any reason, is win-win for everyone.