I can understand a little bit of thinning on the brows, but overly-plucked or waxed eyebrows on men or women "just ain't right."
I was at a local bar a few months back, and wondering what it was about the appearance of some of these guys that was giving me the creeps... then I figured it out - they all (the ones that looked creepy) had waxed eyebrows, and every one of them looked like Joan Crawford.
There is one ethnic group (I won't mention which one, if you've seen it, you know which one) where it is fashionable for the women to completely wax off all eyebrow hair, then draw a thin dark line in where the eyebrows should be. A dark, heavily-applied lip-liner (think clown-lips makeup) completes the look. I'm not a big fan of makeup to begin with, but some "fashions" just look silly to me, and they eyebrow thing is in that category.
While we're at it, I won't cry when the "rooftop" hairstyle for the guys goes by the wayside.