That look babies get when they are pooping, a tight lipped, smile-like grin?
Why do people do that as adults when they do something stupid while driving?
“Sorry…I was in a hurry….I obviously have to poop, and am barely containing it, so, outta my way…”
Same thing happens at work when you pass someone you don’t really know and make awkward eye contact…they give The ShGrin…..
“Hi….Don’t know you well enough to talk or gesture, but here is what I look like when I need to poop…it will have to pass for a smile….”