Maybe it's your GTK theme? I would certainly call its UI tight and professional-looking in Kubuntu (even a bit too "nice-looking", as there's not much colour w

Maybe it's your GTK theme? I would certainly call its UI tight and professional-looking in Kubuntu (even a bit too "nice-looking", as there's not much colour with which to identify icons at a glance; Blender looks like it has the same problem). The default theme on Windows does look kind of clunky, but it's never bothered me.