What Tweak, Program, ... changes a Desktop Environment from unusable to great for you?

I have used Linux on and off for 15 years. I consider myself a casual user and stuck to the mainstream DEs (mostly KDE, XFCE and some Cinnamon). Gnome has been a hurdle for me before and after the big version 40 changes, I couldn’t get my head around how they handled the workspaces and workflow. At some point I I tried out an...