Anybody who says things like "(insert OS here) fucking sucks." No OS is so great that it deserves to be the one true OS; no real OS is so bad that it should never, ever be used, ever. Anybody who even attempts to convince you of this is an OS Zealot. Watch:

MacOS 9 & below: Pretty. User friendly. High Design. Slow.
Windows: Popular. Wide user base. Unstable. Unstable. Unstable.
Linux: Stable. Stable. Stable. Open source. Only easy to use if you know how to use it. You don't know how to use it? You're screwed...

And so on....