To an Apple fan, Steve Jobs' "one more thing" was like Christmas morning as a kid. After you'd opened all your presents and gotten lots of fun, neat stuff but you're doing the math and it kind of looks like your sister got more stuff than you did.
Then your parents come walking into the room with a big wheel that you thought they'd never actually get you.
As you can see from that collection of “One More Thing” introductions, early in his return to Apple, Steve literally acts like he almost forgot to introduce a product that has likely been in the works for years, involving hundreds, if not thousands, of people. Understanding the reasoning for this well-orchestrated and completely manufactured moment gives you a glimpse into the identity of Apple.
I get the impression that Steve Jobs was one of the key drivers behind the theatrical side of Apple's presentations. Not that there aren't plenty of people there who also enjoyed it - I think he really enjoyed getting to do the big reveal. I hope Apple keeps having fun with the theatrics of announcing new hardware and software. It conveys a certain amount of pride in the products that they're building and excitement about the future of Apple's chosen direction.