I can’t say it more clearly, nor can the rules of the road.
THE LEFT LANE IS FOR PASSING ONLY!
The left lane does not exist for you to pick what is “fast enough” as*hole!
If you are not passing another car in the middle lane GET THE HELL OVER and let those of us who want to pass you, do so. It’s not an ego thing, it’s okay if you get passed by my Prius. Maybe if you’re lucky you can laugh at me when you see me pulled over a few miles down the road.
GET OUT OF THE LEFT LANE and let others pass!!! That’s what the left lane is for!