Macs are ridiculously overpriced. Macs regularly ignore mainstream industry trends. Mac OS X is merely a locked down version of open-source Linux. There's not even right-click. The Dock, and general screen layout svck. “It just… doesn’t work.” (Macs crash, freeze, and have evil viruses too.) Software and hardware options for Mac are lame, or slim at best. Gaming, and graphics in general, svck on Macs. Macs are not flexible or customizable. And plenty more reasons...
Macs are, aptly, expensive. There is, in fact, R-Click in OS X. On the whole, OS X is by no means broken as you've described it, but was probably just unfamiliar to you when you used it. People are generally creatures of habit and might think anything they are familiar with from using Windows can be extrapolated and will be applicable on another OS which simply isn't the case, but that by no means makes an OS inoperable. As for gaming on a Mac, that all depends upon the hardware. Fallout 3 and Oblivion both perform exceedingly well with everything maxed out (+ HiRes texture replacers) on a MacBook Pro, so the statement, "Gaming, and graphics in general, svck on Macs" holds no water unless you're referring to a dinosaur of a Mac... :shrug: As for customization, I've a Windows install which is every bit as customizable as any other and, from all I've seen, OS X is every bit as malleable as Windows, but is just ...different.