it definitely makes sense to give people things, to think of them as tied to actions, even to feel entitled, for plenty of practical reasons. but nothing is tied to anything, it's merely a figure of speech meant to inspire trust. but even if you do trust someone and believe that they should trust you, that doesn't change the liklihood that you will sometimes disagree about what is best for them. and while you can get a lot of mileage by securing the trust of others, there must be some cases where your interest trumps theirs. who deserves anything then? at these points people make up excuses about somebody else being more deserving of some other reward that may not even be logically related to the situation.
we all act principally out of self-interest, it seems, at this point in our evolution. it can be very hard for a person to accurately judge the differences in personal satisfaction and stimulation that are liable to result from their actions and inactions. but they will sometimes be capable of influencing themselves by listening to predictions of how other people will behave in the form of arguments. most political argument is about behavior, but argument is behavior, I think that's what makes it so inherently dubious and we all prefer to listen to ourselves. Is that what Rawls said?
well despite how hard it can be to listen to someone without internally interrupting, correcting, or reinterpreting some of what they say, we are sometimes able to do it and genuinely change our own minds about how to become happier through sincere changes in our behavior. they are still motivated by selfishness. but they often carry great benefits to huge numbers of people, some of whom are able to pay it forward or pay it back. perhaps one reason the film 'pay it forward' seemed as plausible as it did was because people are familiar with the desire to stay in someone's good favor after they have just given you a gift and insisted that you not immediately reciprocate. often that feeling is expressed by the desire to give something to someone else, something they'll truly appreciate. why do people feel guilty upon receipt of such a gift? why do they feel bad when we really meant for them to feel good? it is because of the misunderstanding of this word 'deserve'.