Imagine we’re moving. And we have two friends, who both extend an offer to help.

The first friend writes us a check for 1,000 dollars to help with the moving expenses. Incredibly generous. The second friend doesn’t offer a dime, but instead comes to our old place, helps us pack up every box, drives with us to the new house, and unpacks everything with us into the early hours in the morning.

Fast forward two weeks later. Both friends call you to ask for a favor. Which friend are we more likely to help?

We would choose the second friend. But why? If we were to try to explain, we collectively would flow to the same, natural response… “Because they would have done it for me.”