Well, whatever you want to call it. The tossing it behind his back in a goofy manor. It’s not just about being goofy, but also him tossing the lightsaber like it means nothing to him.
I get what they were trying to do. They were trying to have hermit Luke act like a goofball similar to how Yoda acted in Empire. It just didn’t work and I doubt anyone 2 years ago would have said that’s how they wanted that Rey/Luke scene to go to in TLJ.
Completely agree.