Why, oh why, do people insist on using a shade of grey as a forground color? Grey is harder to read against any background color than plain black (or white, or most nonzero-hue colors), my eyes are already messed up as-is, and I’ve never heard of anyone’s eyes improving over time.
Notable offenders include a lot of GTK+ themes (the GtkFrame’s label widget rules—which doesn’t work where a V/HBox pair is used to group widgets, like Nautilus’ File Management Preferences dialog), and WordPress’ default template. 🙂
James Cape 
I suppose some folks think that grey text looks “softer” and thus is easier on the eyes.
I hate to squint at some pages that use #ddd against #fff or some such. I miss the point, too, sometimes, though I am not so hostile to grey 🙂
Grey reminds me of pencils, like black reminds of pens. Never had a problem with either, though.
It’s more getting fed up with having to squint to read a particular web page—even after bumping up the font size. Easily solvable with View->Style->None, but irritating nonetheless.
It actually reminds me of the tiny-text craze of a few years ago, where every website on the internet had to have hardcoded 11px sans-serif fonts.