Emotions, it seems, serve as "governers" (bill), or regulating agents between our "inner calculator" and our "outward behavior" (Ridley). Trivers descibes emotions as "polished toolkits" of a species defined by mutuality and cooperation. Guilt repairs relationships. Unsolicited kindness promotes reciprocal kindness, (or resentment). In a sense, manipulative how-to's for getting what we need. They serve a purpose; survival.
Then there's something called the Commitment Model which says that there are individuals who may be kind for the sake of kindness alone, not recognizing the immediate payoff. The fact that they do not recognize the payoff does not negate the reality that the emotion still serves to manipulate an intended return benefit. The kindness is, in a sense, banked for the future.
Eric Berne talked about the manipualtive human process of overt and covert transactions where two or more individuals engage in what he terms "Games", which results in an intended "payoff". These transactions usually result in "rackets" (bad feelings). As the "games" continue, each side collects psychological trading stamps to be cashed in later. In much the same way, we obtain positive strokes of human contact and recognition. When not readily available, humans employ games to obtain strokes.
Berne further talked about the concept of "scripts" in which parental stroking, whether supportive or critical, is imposed on their children. From this stroking children gain a sense of whether or not they, as individuals, are worthwhile. Children also gain a sense of who and what, in the environment, is acceptable or not acceptable, based on parental standards. They carry this scripting with them, throughout their lives. Are we genetically determined to be more or less altruistic, cynical, selfish, etc., or are we "scripted". A little of both?