Overly aggressive, you got me. If I've sounded ignorant, that is either my fault or your love of mac getting in the way.
As a computer user I am very experienced. Programmer I am not even close.
I do very well with what some obviously very intellegent people intended for me to do with these machines that they created and advance. That experience is extensively in graphic design. I first put my hands on a mac when it could output a professional graphic font and the IBM could not.
Anyhow, enjor your mac.
I'm a PC dude. I do have some experience with the mac though, and am getting up to speed with iPhone development. So I am not yet at the "fan boy" level, but am working on it :-)
The reason I suggested you were being ignorant is that your original post actually illustrates what Steve Jobs was talking about. As has been explained already, that is an app going off into the weeds and tying up its message queue (not "crashing the system"). The only time I see that on my mac is when I am at hulu.com watching a flash video in the browser.