One of the reasons I enjoyed Pay It Forward so much is that I've been living by the Golden Rule since I could talk. My earliest memory of a generous act:
My little sister desperately wanted a pet turtle. So i went down to the nearest pet store, an easy walk from our house, and looked over their stock. They all appeared to have soft-shell disease, a thing pet store red-eared turtles get. So, without returning to or calling home, I hopped on the bus and went to an aquarium store in the next town; a big, well-stocked place with knowledgeable staff, one of my favorite places on earth. I found a healthy turtle and brought it home.
Mom told me afterward how eagerly and impatiently my sister had waited for me to come back - rushing out to the driveway every few minutes to look down the street. And then she complimented me on my generosity - which hadn't even occurred to me; I was just having a good time doing the right thing.
My life, by the conventional definitions of material success, is pretty crappy, but nonetheless I've been paid back many times for that little turtle.