A lost object returned anonymously can make the world feel briefly more trustworthy.

What does the work here is the missing name. If someone hands your wallet back in person, there is a small exchange to complete, thanks to give, a face to attach it to. Returned anonymously, there is nothing to settle and nothing anyone gained, which makes it unusually clean evidence about how people generally are. One such event can adjust a whole week of assumptions about strangers.

You can produce that effect for somebody at almost no cost. Hand something in without leaving your details. When it happens to you, let it register rather than filing it away as luck.