I offer, on me let thine anger fall;
Account me man; I for his sake will leave
Thy bosom, and this glory next to thee
Freely put off, and for him lastly die.
This excerpt is found in lines 237-240 in Book III of Paradise Lost. It is spoken by the man who I believe committed the last truly altruistic acts on earth: Christ. Christ was perfect and everything that he did he did for God and for us. He did it with a pure heart. When he offered himself to this task to atone for our sins, his language is a tell that he is doing it for anybody but himself.
Here's how I feel...people do good things every day. We all serve and we all do these little acts of kindness just because we know it will make the other person feel better. We even go so far as to not expect any sort of reciprocation or reward for good behavior. I would have assumed that this is altruism, but even if one doesn't expect something in return, one can still get the good feeling of knowing one did something for someone else...which is a benefit--not intentional--but a benefit nonetheless. That person still got something for themselves out of what they thought was a selfless act, and I believe that makes it impossible for the act to be truly altruistic.
(Of course, I'm unable to articulate that point as well as several other scholars could, but I hope you get the idea.)
You'll get to thinking about this and realize that, by the way this is approached, there's no way to serve someone 100% altruistically, because, inevitably, you will always get something in return, even if it's the good feeling you have for doing it. Even if you don't necessarily want that feeling!
I think this is okay.
That's not to say that we don't try in this life. We shouldn't stop trying to be Christ-like because it's such a difficult goal to achieve; I think all we can do at this point is serve to the best of our capacity, which many of us are doing anyway, and do it with as pure of a heart as we can, because I think that's all God would expect from us right now.
What do you think?