Paul, thanks for pointing out the standardization of this bad idea.

http://www.tiac.net/~sw/2003/11/dribble_glass.html

Being in a slideshow on Play is like the feeling of having cruise control on and encountering traffic or tricky turns. Yikes, Duh! Um!--tap the break! All of a sudden the car, instead of being an expression of your will, is an independent heedless projectile with you as passenger. Automated slideshows drop you into that situation unasked. (Except, okay, the feeling in your guts that you're about to physically collide with something is an illusion in this case.)

Non-automated slideshows on the web are often differently awkward: individual pages with buttons (that you often have to scroll to reach) for back, up and next that are just links to pages, so you pile up a list of pages in your browser's Back history. And of course it doesn't start fetching the next page until you hit Next.

"This is one example where Apple got it wrong *because* they sweated the details." This had me unsure for a second, but, No. Microsoft Word, for instance, has all sorts of automated features that required thoughtfulness and effort to add--but happen to be wrong. So, it must be that "sweating the details" means sweating until the bad ideas have left your system. Apple failed to sweat that automated play button out.