Yesterday I was eating in a downtown area. I probably saw 8/10 people walking down the sidewalk with masks on.
I'm considering publicly shaming them, since that's what gets them to wear a mask in the first place.
In college, we used to drive around and ask "Do you know where the library is?". If they knew, we'd just shout "NERD" and drive away. Completely immature and stupid, but I wonder if a similar tactic would wake a few people up.
Feel free to whistle happily. And / or sing: "I once was lost, but now am found; Was masked, but now I breathe..."
And pretend not to understand them, like they're not speaking clearly. And smile, especially at the kids. You can also practice deep breaths, making mask wearers envious.