Vista because of license shenanigans. I tried to upgrade from XP and the license wouldn’t activate. Support told me my upgrade license wasn’t compatible with my XP license, like pro vs home or some crap. I was reinstalling Vista every 30 days for a while, I even got it down to like 15 minutes using a slipstreamed DVD with all the stuff I cared about being installed with the OS. It was manageable but annoying since I paid for the OS and the upgrade but couldn’t really use it. Then I took intro to unix and found out linux is free, I’d heard of linux but didn’t know it was free. I didn’t know what a distro was, I wasted a bunch of time trying to download linux from kernel.org and I couldn’t figure out how to get linux to work. Eventually I stumbled upon Ubuntu. Folks, you might not believe this but once upon a time Ubuntu used to be great for newbies. I can still hear the startup music (which was the style at the time) and the african drums. My printer just fucking worked. Firefox and libreoffice just worked, although I quickly learned to turn in deliverables as pdf exports. There were some learning pains but nothing that was any more difficult than random shit that pops up in windows, at least with linux I might get a useful error to point me in the right direction and there was always someone out there smarter than me that posted how to fix it. I haven’t looked back.