So what's "just right", then? Windows and its Swiss cheese, or is even that too paranoid? Oh, but I know; you want a machine that just does whatever anyone wants it to do, with no regard whatsoever to security. "Mommy, I DON'T WANNA PUT MY NAME ON THE PAPER FOR SCHOOL!"

OSX is not overly paranoid. Overly-paranoid operating systems exist, of course; you'll find them in use by the NSA and similar agencies. But making sure that someone doing something dangerous is actually allowed to do it is not paranoid.