Everyone, does everything, whether good or bad, in (his) own perceived (whether conscious or subconscious) short-term or long-term best interest, with very few exceptions.
This statement of what I believe gives me an insight into other peoples behavior and helps me deal with them, has caused a lot of controversy with my friends. Join in.
People give money to a poor person because it makes them feel good, or moral, if you wish. They are angry because it is the best way for them at the time. They do a good job, although they hate it, because they like to eat.
The exceptions have to do with throwing yourself under a bus to save a child or the like.
Anytime the intellect gets involved in making a decision, subconsciously the mind is trying to figure out what is best. The decision is not always correct, but you can be more effective in dealing with people, in phrasing requests, to appeal to the behavior, sometimes subtly.