Yeah, it's one of those things that once you notice it, you can't stop seeing it everywhere. It does seem to mostly be women doing it. I'll sometimes just keep looking until I find someone that don't have their mouth open.
This is a WIP for a vanitas prompt I've been working on yesterday and today. Hopefully I can pull it together... not sure how happy I am with it so far.
I planned on working on it more this weekend, but ended up binging Evangelion on Netflix.