An ordinary courtesy becomes especially visible in a place where it is usually withheld.

The same small act is worth more in some rooms than in others. A greeting in a friendly shop passes unnoticed; the same greeting where people are usually processed rather than met can change somebody’s whole hour. Value here depends on scarcity rather than effort. Being ordinary in a place that has stopped being ordinary is a real contribution.

Think about where you go that runs cold: a clinic waiting room, a service desk, a late train. Do the plain courteous thing there without deciding in advance whether it landed. In those places you are rarely the only person who noticed.