We are all bridges in life. Bridges for other people to get to where they need to go, or bridges for learning to help people learn what they think they need to learn, or maybe what you think they ought to learn.
Whether people appreciate you or not, remember that their success or failure was, in part at least, facilitated by what you did for them, and if, in your heart, you did what you did to help them, your efforts and thoughts will be rewarded. In the bible this is expressed as bread cast upon the water comes back tenfold. Or something of that nature. That's life.
Sometimes I feel like my efforts are unrewarded or un-noticed, and I have to remember that all things will come back to me in one form or another, and that I don't do things for the reward, but for the fact that they should be done and I am in the time and place and capable of doing them. That's all.
That is my beef with the christian heaven and hell concept. If christians (or religionists) do things because of the "reward" that is waiting for them in the afterlife, is that really behavior that is from the heart? It could be, but it is likely not. So if an atheist does a good deed for no reason but the deed was the right thing to do, is he more righteous than the person who expects reward in the hereafter? In the end it doesn't matter too much, just that the deed was done, I guess.
