It drives my wife nuts when I reinstall an operating system. She'll just get used to how things are working, and then I go an format the drive and start over. We've actually gotten to the point that I'm not allowed to do anything but fix her computer, and only reinstall when things are totally botched.
But I format my drives all the time. At work, I used to do this because Windows would act wonky, and the most efficient way to fix the oddities was to reinstall. I don't really use Windows very much anymore, but I still reinstall my Linux machines just as often. Probably more so.
I think this is due to a number of issues:
* I really like to install Linux. I love that "finding drivers" is almost never required. There's something about a freshly installed OS that appeals to me. And that OS being Linux, well, that's just cooler yet.
* I like to play with different distributions. I've tried pretty much all of them, and they each offer neat "twists" that make them fun to play with.
* I change my mind all the time. ALL THE TIME. For several weeks, I'll desire to sit at my desk, and use the old IBM tower I have to write with. Then, I'll get the notion that I need to be mobile. So I'll move the IBM and set up a makeshift docking system for my laptop. Then I'll think Kubuntu is cool. But that's on my dual boot Mac, so I switch that around. It's unending, and my wife thinks I'm insane. She might be right.
* Linux has too many options, and I can't settle on something I like. Largely, I've settled on using Google Docs for my writing, but with all the free options available, it's really hard to choose one. Software monogamy is too cruel a rule.
Honestly, I think the big reason I reinstall my operating system so often, is simply because I can. It's free. FREE. In every sense of the word. I can download the latest, coolest OS for free. I can get the bleeding edge Ubuntu disk, and see what it's like. I can try Puppy Linux, because it's small, and that's cool. I can install Fedora, and try to figure out why it takes 273 CDs to install. ;)
So if you're bored this weekend, feel free to reinstall your operating system. It's tons of fun. One warning, however, if you share your computer with your significant other: Maybe you should just read a book instead. :)