I decided to reply to a rude comment on a local news post about a new park, and the person who wrote it actually apologized after I asked them to explain their point.
I saw a comment saying 'this park is a waste of taxpayer money for the lazy' on Facebook, so I replied with 'Can you explain how a free public space for kids to play is only for lazy people?' and after a few back-and-forths, they said 'okay, maybe I was just in a bad mood, sorry.' Has a simple question ever changed the tone of a comment thread for you?