Let's say you're a kid. You've convinced yourself that your parents are going to get you a pony for Christmas. Instead, they get you a pair of rollerskates.

You really like those rollerskates. You have a good time rollerskating every day. And your parents never were going to get you a pony. But, still, you convinced yourself you were getting a pony, and so you're disappointed.

If you're an Apple fan, you're probably like that kid. You convinced yourself that Apple was going to announce amazing new technology at its Worldwide Developer Conference this week. In the time leading up to the conference, the rumors were flying on the Apple blogs -- as they always do -- that Apple was going to announce a new tablet computer, an iPhone Mini, that Steve Jobs was going to put in a surprise appearance. You expected those things. And, when none of them materialized, you were disappointed -- even though the announcements Apple did make were solid, with significant improvements to iPhone hardware and software, the Mac OS, notebooks, a new version of the Safari browser, and more.

By any reasonable standard, that's a pretty big array of substantial announcements. But Apple fans are disappointed. For example, Nick Mokey writes at Digital Trends: "Apple iPhone 3G S Disappoints at 2009 WWDC." Lance Ulanoff writes at PCMag.com, "Apple Delivers iPhone 3G S and Leaves Out Much More." Why the disappointment?

Partly it's the rumor mill, which inflates expectations. But there's something else at work here: Apple has delivered the pony many times in the past (so to speak). In the 12 years since Steve Jobs came back to work at Apple, they've delivered eight amazing announcements which revolutionized existing businesses, threatened established industry leaders, and changed the way people think about technology.