A few quotes from a TED talk by David Pogue:
06:44 - The software upgrade paradox - If you improve a piece of software enough times, you eventually ruin it.
20:41 - This cult of doing things right is starting to spread.
20:57 - If you are among the people who create this stuff: Easy is hard. Pre-sweat the details for your audience. Count the taps. Remember the hard part is not deciding what features to add, it is deciding what to leave out. And best of all your motivation is simplicity sells.
"David Pogue says 'Simplicity sells'," Video on TED.com, TED 2006, posted June 2006, www.ted.com/talks/david_pogue_says_simplicity_sells.html.