An anthropologist looks at the motivations of ground-level military troops, and finds them amazingly noble.

Profound.

Is it possible that America is actually a nation of frustrated altruists? Certainly this is not the way that we normally think about ourselves. (Our normal habits of thought, actually, tend toward a rough and ready cynicism. The world is a giant marketplace; everyone is in it for a buck; if you want to understand why something happened, first ask who stands to gain by it. The same attitudes expressed in the back rooms of bars are echoed in the highest reaches of social science. America’s great contribution to the world in the latter respect has been the development of “rational choice” theories, which proceed from the assumption that all human behavior can be understood as a matter of economic calculation, of rational actors trying to get as much as possible out of any given situation with the least cost to themselves. As a result, in most fields, the very existence of altruistic behavior is considered a kind of puzzle, and everyone from economists to evolutionary biologists has become famous through attempts to “solve” it–that is, to explain the mystery of why bees sacrifice themselves for hives or human beings hold open doors and give correct street directions to total strangers. At the same time, the case of the military bases suggests the possibility that in fact Americans, particularly the less “affluent ones, are haunted by frustrated desires to do good in the world.

Altruism is a very difficult philosophy to sustain. It is highly disheartening, to say the least to selflessly give and to unfortunately see only takers and selfish guys prosper and to see the good guys getting undervalued and getting trampled upon. I agree that we should not do stuff in the hope of getting returns, but sometimes the sheer ingratitude of people rankles. 

Also it's best to not give to everyone. Figure out who is worthy of your giving.