Isn’t it interesting, when we pay for something, we have an expectation of what that transaction will deliver to us, but there is little sense of lingering obligation.
However, if we just do something for someone, any small piece of kindness or consideration, it creates a bond, and often a feeling of obligation that the kindness requires some reciprocal consideration on the part of the receiver.
This reciprocal obligation dynamic exists in the best demand chains, smoothing the path through the chain of whatever product or service the chain is set up to provide.
Any chain is a set of transactions, but the dynamics of a transaction are nowhere near as important to the individuals performing the transactions as the overall performance of the chain, and so they use initiative, alter the status quo, innovate, and generally go that bit extra, recognizing implicitly the value of the action to the performance of the chain, and it is their contribution to the performance of the chain that is the motivation, just completing the not the immediate transaction.