Yosemite is the most beautiful OS ever, no question. Only let down by the hideous dock background. However cdock (free) has been released that has a bunch of settings that make the dock even more ugly. Except for one particular setting, which completely removes the background, and with this little tweak, Yosemite is not marred with this incongruous and pointless dock background. What I don't understand is that all the icons on mac just like iOS seem to have been designed to work on a transparent background whether they are light or dark and whether the background is light or dark. See the screen shot below for example. And seeing as iOS icons are basically on a transparent background, I cannot understand why Apple did not leave the Mac dock with a transparent background by default.