Microsoft's answer would be that it's all because of other non-microsoft software you have installed.
The problem is probably that Microsoft is too big, and they have a horrible business policy.
I'm sure they have both very good and very bad programmers, but when you have very large teams, the chance of the few very bad programmers doing something horrible increase significantly.
The other problem is that their business policy is to eliminate all compitition, so naturally, it they put in a few crashes into their software here and there that they can blame on third party software, that's all for the better.
Yeah in Linux it's easy to get bitten by the tweaking bug, just because you CAN. I've been using gentoo for the longest time and lots of time was always spent on compiling and configuring etc,... though usually once I have it as I want I can start being productive. On my other machine I installed ubuntu(dapper), which pretty much worked out of the box, I didn't even need to compile any drivers into my kernel. So that saves some time, offcourse now i'm stuck with a gnome desktop. I always used either fluxbox or afterstep. I haven't gotten around to changing it yet, I might actually switch back to afterstep later, but it works for now. I'm not gonna start fiddling around too much again now that I'm finally being somewhat productive