The use of duty

A vivid memory: As a small child I was contracted to make floating candles for a wedding.

It was also my duty to keep them lighted all night. Patiently relighting them any time some water splashed. Effortfully a candle from the far side of the pond closer to me.

The sense of duty was strong. Even though what I did had no use then, or now: I still feel good that I did that well.