My fondest memory of OS9 was how often it crashed, as in at least once a day. An app would freeze in a way that OSX could easily overcome with force quite, would bring OS9 to a total lockup and forced reboot.
Then again things were so much simpler, there were only two ways to setup the finder, pictures or list, and the launcher for your apps, rather than the dock. Have a number of old games that are OS8/9 only. Miss those days, but like the downfall of Netscape Navigator, time moves on. To think at one point I was an OSX hold out, don't think I switched until just before Tiger (10.4) came out.