Achilles was dipped in the River Styx by his mother Thetis so that he would be invulnerable—in every area except his ankle, where she held him. A poison arrow ultimately found the vulnerability and the great, albeit temperamental, warrior of the Trojan War was brought low.

An ankle? One reason to love the Greek myths is their narrative drive, which combine film-ready heroes and drama and faith and betrayal with the profoundly anti-Hollywood ways in which the Olympians punish hubris: No movie hero is going to be felled by a ligament tear (“The Bourne ACL”).

The iPad, by any reasonable accounting the tech marvel of 2010, is the poison arrow seeking Microsoft’s heel. It doesn’t matter that there are “only” several million iPads in existence, just as the number of IBM PCs sold in 1981 was not the issue. The issue, now as it was then, is the importance of “personal” when it comes to computing devices. When people become delighted by a machine, they want that delight at work. Corporate policy or not, immediate practicality or not—it didn’t matter then, it doesn’t matter now.

I recently heard an IT admin specifically ask about supporting new technology “such as iPads.” We software developers may complain about the rate at which we must learn new technologies, but pity the poor IT team, which is already being pressured about supporting a device that didn’t exist a year ago! And the ensuing conversation foreshadowed the inevitable outcome.

The IT admin made perfectly valid points about security, resources and policies. And then someone asked how many of those sitting around the table had connected their smartphones to the corporate network in defiance of those very same issues. It may not have been the most polite way to make the point, but resistance, as the Borg have taught us, is futile.

So too, inevitably with iPads. People will figure out how to connect them to, at least, the corporate e-mail server. From there, it’s just a matter of time for them to struggle with the challenge of reading and editing documents. Here’s where the poison enters…

The iPad may be wonderful for reading and writing e-mail, but for document manipulation, one wants a keyboard. So if you’re an iPad enthusiast, for your next laptop you’ll undoubtedly prefer a MacBook Air or Pro. And once you have your “couch and airline-seat solution” in an iPad or MacBook Air and your “hotel and working-from-home solution” in a MacBook, your weaning from Microsoft is almost complete. You’ll undoubtedly buy Office for Mac, only to discover that it runs poorly in comparison with native Mac alternatives. And soon enough you’ll be wearing black turtlenecks and assembling Antikythera mechanisms out of Legos.

The enthusiasm generated by a truly “personal” computer is, of course, how the PC so shockingly displaced the mainframes of the 1970s. The new beige boxes were toys compared to the powerful mainframes in the climate-controlled basement, but people preferred to work with WordStar and Lotus 1-2-3 rather than with the vastly more powerful (but frustratingly bureaucratic) sanctioned mainframe tools.

“But WordStar and Lotus 1-2-3 were productivity tools par excellence!” you may cry. “The iPad is the opposite: It is a game-changer for how you spend your time on your couch, not at your desk!”

But the PC was originally about enthusiasm too. If you’re old enough to remember TRS-80s and Apple ][s and Commodore PETs, I bet you remember Hammurabi and Oregon Trail and Hunt the Wumpus more than you remember dBase I.

I don’t know that the touchscreen will inspire a productivity tool with the lightning-strike power of VisiCalc (it’s been 30 years and what, really, has come close?), but I do know that enthusiasm drives sales and software development in a virtuous cycle and, right now, the iOS community is vastly more enthusiastic than the Windows community. Microsoft has done an absolutely stellar job squandering a seven-year lead in tablet operating systems and now has millions and millions of arrows flying toward its vulnerable heel. Just ask your IT department.

Larry O’Brien is a technology consultant, analyst and writer. Read his blog at www.knowing.net.