I couldn't even tell you the last time I felt like I "made somebody's day" at work. But maybe I did. I changed out the water cooler this morning and I suppose it's possible a coworker secretly on the verge of dehydration was extremely grateful.
You never know, you might quietly make someone's day a bit brighter. Sure, it could be one of those constant complainers who never leaves positive reviews on Google, but has left 50 negative reviews. Don't bother doing anything nice for those sorts, they won't appreciate you anyway.