A borrowed umbrella makes a stranger’s dry arrival partly your doing.

Small lending puts you inside somebody else’s day for a moment. The umbrella you handed over walks to a station you will never see and gets somebody to an appointment in a state they would not otherwise have arrived in, and you will hear nothing about it. Most of the good you do is like that: real, untraceable, and finished without a report. It counts anyway.

Lend the thing when the thought crosses your mind, without arranging for it to come back. Accepting that you will not learn how it turned out is the small price, and it is worth paying more often than most people do.