Give somebody a lift regularly and within a year you know a road you'd never have driven down, a family's names, which shop stays open late, what a dialysis schedule does to a week.
Generosity keeps enlarging the map by accident. It's not the reward anybody sets out for and it's the most dependable one: you get pulled into lives arranged nothing like your own, and the world stops being the four or five settings you'd been circulating between.
A narrow life usually isn't caused by lack of curiosity. It's caused by never having a reason to be somewhere unfamiliar. Giving keeps producing reasons.