Every time I have to explain one of OS X’s bizarre, (sometimes
arguably) buggy behaviors or windowing idiosyncrasies to my
father in law, I dearly wish the iPad had been out when he was in
Exhibit A: Open Mail, find a message with a zip attachment, and
double-click it. Nothing happens? Oh something happened. Archive
Utility opened to work its magic on the zip file, but you missed
its appearance in the Dock if you blinked. Don’t see anything
else? Of course you don’t, because Finder opened a new window to
reveal the spoils of Archive Utility’s victory behind Mail and
didn’t bother to tell you. No Dock bounce, no Finder brought to
the foreground to show you the folder.
Great example. iOS enforces a visual obviousness that makes computing better for nearly everyone. If you do something, the result will be shown to you, front and center.