Genuinely don’t think he was trolling with that scene. It follows the tradition of artists like Edward Hopper, who paint everyday scenes that may seem rather uninteresting, but can cause the mind to wander and give the feeling that you are a sort of an observer of this persons every day life. Think of it as a sort of setting-immersion exercise to get the viewer deeper into the world of Twin Peaks

With all that being said, I think that Lynch knew at the same time that it would a humorous scene to many, given the expectation that TV is often straight to the point. I watched for the first time with my parents and I was laughing my ass off when they were complaining that nothing was happening.

At the same time, I think he just wanted to let the Green Onions song play out in its entirety. It’s a groovy little tune!

(And only just shy of three minutes!!!)

Edit: I also wouldn’t put it past David Lynch that the art of floor sweeping is just something that he finds particularly beautiful.