The answer to this question is rooted in classic game theory. Let me explain:
Imagine that two people are facing a negotiation for a piece of property. There are four options. The most basic ones are more and less – the buyer can pay either more or less for the land. However, there are two more options as well. Both the buyer and the seller can create extra value in the transaction by giving up things that are less valuable to themselves, but more valuable to the other person. E.g., the seller knows that there is no lead in walls and so it would be almost cost free for him to give a financial guarantee to that effect; while the buyer might be very nervous that he will have to immediately spend a bunch of money deleading the walls and would raise the purchase price if he could get such a guarantee. Meanwhile, the buyer has a lot of liquidity and could close the deal almost immediately, while the seller is borrowing money on bad terms to stay afloat until the deal is complete.
The highest value will be achieved if everyone “sells” the value that is worth little to them for an amount between the value to them and the value to the other. However, for each individual person, the best decision in each individual circumstance is to claim the value for themselves. If the seller can refuse to offer his guarantee and instead simply wait for the buyer to offer an early closing date, he will be better off than if he offers the guarantee. Meanwhile, if the buyer simply refuses to offer the early closing date, and simply waits for the seller to offer the guarantee, then he will be better off than if he offers the guarantee. Because of this “self-centered-ness”, the transaction might fail, and even if it goes through it is not as “efficient” as it could have been.
In order to overcome this problem, both parties need to trust that the other is going to act in the interests of the two of them. If that happens, they will both be giving, not only as a result of their own altruism, but also because their trust allows the two of them to gain value that would otherwise be impossible to unlock.
Thus, in “giving” through an understanding of mutual trust, it is not only possible but likely that you are personally better off than you would have been by simply waiting to receive.