If you have any additions or comments, please send them my way.

Take all of these with a pinch of salt: like a fortune cookie fortune, you should add something to the end of each entry along the lines of "...when it works."

• PostScript. PDF.
• Cut/Copy/Paste (although it's amazing in how many situations they don't work!)
• Unix pipes.
• All the unix command line utilities and applications (find, grep, awk/perl...), which work with said pipes, so they can leverage off of one another.
• VMS's automatically backupping file system. How many times have you screwed yourself with \rm * by accident after drinking too much coffee? I just wish the backups were hidden by default so they wouldn't clutter up directory listings.
• AmigaOS's idea of public screens.
• AREXX, and the fact that everyone supported AREXX ports in their Amiga applications.
• Alt-Tab hot keys for application switching.
• The MacOS's Finder window title bar feature (option-click? on the title) which shows the path hierarchy, and you can select any of those to open.
• Find File dialogues that let you actually open the item and its containing folders (anywhere in that hierarchy), like in MacOS, unlike in Windows.
• Keyboards without numeric keypads (the keypad pushes the mouse too far away).
• Ergonomic keyboards (like the original MS natural).
• Big fat trackballs, rather than using a mouse, like the (poorly named) Kensington Turbo/Expert Mouse.
• The optical red dotted ball system Logitech uses in their trackballs. Crazy!
• Data-driven programming e.g.: resources.
• Functional programming. Strict strong typing.
• XML.
• Magic lenses: say you could put your mouse over part of a web page, and see it's underlying HTML through a lens, rather than having to view the entire source and find the appropriate stuff.
• Paradroid, Drop Zone, Elevator Action, Dig Dug, Rally X, I Robot, Juno First, ...