I miss webOS dearly. I still have my HP TouchPad. It could put apps in the background and pick up like nothing happened from a recents screen in 2009. IIRC iOS wouldn't follow suit until 4 years later.

There was also the fantastic cross-device sharing feature. If you had an HP phone as well as the touchpad, and paired them via Bluetooth, you could place phone calls from the tablet, as well as being able to pull up a web browser on the phone and tap the phone against the tablet and have it pull up the same page on the bigger screen exactly where you left off. I've never seen anything more recent even attempt something similar. The closest I've seen is KDE Connect which adds a button to the Android share menu that opens the URL on a connected tablet, desktop, or laptop. Still all but seamless, but not nearly as cool.

And Exhibition Mode. Downloadable, interactive screensavers for when the device is locked and on its charging pedestal. Apple didn't start trying to pretend they invented that until 2020.

Early versions of the TouchPad OS even played the Angry Birds slingshot sound when you swiped down to dismiss an app from your recents menu. I miss little touches like that.