Probably because I'm a long-time PC user who relatively recently switched to Mac for my personal use, plus I still use Windows a lot in work. Still, 99.9% of my frustration comes from the PCs, and even did when I was a Mac newbie. It was easier to learn OS X than to keep dealing with Windows (which I've been using since the version 2).
Basically, there has to be an immediate or potential monetary return for me to deal with a PC anymore, unless a family member is begging me for help and I'm in a generous mood.
Otherwise I'm sticking with my Mac. The platform won me over on its merits with quality and attention to detail.
To hit on the cooling subject again, it looks like the iMac's heat could be causing the screens to turn yellow, adding to the problems of flickering and blacking out screens. I think there is going to be a quiet recall. There's lots of video on YouTube now of the problems.