[mercer]

Wonderful example!

I'd add that just looking at how families or circles of friends operate is also enlightening. The most cynical view is that these interactions are 'debt' based, but practically speaking that often isn't true either. I help my mother not because I calculate the effort she has invested in me or the value she brings me. I just do it because I love her and I don't need to think about how I've come to feel that way (which very well might be based on measurable behavior on her part).