No act of kindness, no matter how small, is ever wasted.

Small kindnesses feel negligible partly because you never see where they land. The person who received one rarely reports back, and their reaction may arrive weeks later in something you never hear about. That invisibility is not evidence of nothing happening; it is simply the nature of the accounting.

Since the effect cannot be measured, the only sane policy is to stop trying and act anyway, doing the small thing you have talked yourself out of because it seemed too minor to matter and letting it disappear from view without needing to know.