I was on a computer in the library last year, and my friend was on the computer next to me, and we were playing Flash games online. Suddenly, his computer froze up, and a message started writing itself that if he didn't get off now, he'd get written up, so he pushed the power button and shut the computer down. Well, he left, and I kept going, until I started to get the message too; the only difference was that I had the mouse down when the message started, which I think broke it, so I got control back, but I got off anyway.
The only reasons Macs get fryked up is because of poor maintenance (or poorly-written software, which isn't Apple's fault). If you take care of your Mac and maintain it like you maintain your car, you shouldn't have any problems. Now, Windows machines are like Fords: they'll break on their own, without you having to do anything.