Users want to complete tasks.  Each of these tasks should be as simple as a toaster.  Push button, insert input, push button, win.<p>Open Mail, type letter, hit send, hear "sent mail" swoosh.<p>Open Safari, enter URL or search term, click Go, get webpage.<p>Push lever, insert bread, wait 30 seconds, eat delicious toast.<p>Open Word, type stuff, hit save/print/email, get happy boss.<p>Open Youtube, enter search/URL, push Go, Laugh.