Always keep in mind that the person you’re talking to has a story just as elaborate as yours so treat them with the same respect you would treat a loved one. I would say something like “hey smartass! It’s made to cover your whole face not just your lips!” Nah seriously though I would probably be like “I know sometimes it can be annoying but it protects everyone better if you wear it over your nose too” There isn’t. If they’re wearing it that way it’s on purpose, and there most likely waiting on someone to say something so they can be confrontational also. You just have to decide if it’s worth it to you to be in that confrontation.
At first, I felt the same way when seeing people wearing masks improperly, I need to scold them, or something. Then I too had a problem, my mask kept slipping and just would not stay up. 1/2″ of excess elastic is all it took from being easy to wear a mask to be a frustrating nuisance. The fit is important and harder to achieve than I thought it would be. I have adjusted my masks to fit better. We will all get better at it. Just keep your distance from those still struggling.