I miss the constrained design of Mac OS Classic. You could use multiple windows even on those puny Mac SE -type 512x384 displays and with some 1024x768 display you could have lots of different things happening for file operations, apps etc. It's weird that X's current windowing system is really bad at this even on 4k displays.

Oh and the spatial file navigation with Finder worked perfectly. Haven't seen anything so awesome ever since Classic got obsolete.