I inadvertently left my water bottle at a ticket machine somewhere in the Tokyo rail apparatus and then traveled 4-6 stations away and reported it to an info booth there. An attendant brought it to me on the next train less than ten minutes later. Mind blown.

It was a heavily insulated water bottle and keeping ice in it made a world of difference as I was traveling at the hottest time of the year.

A small object can be insignificant when it is anonymous but significant to an individual. It's nice when other humans "have our back" at scale.