A terrible usability decision was made with the introduction of the greyscale Finder sidebar. The folders in the sidebar are difficult to distinguish. If colour is so unimportant, why aren’t the applications in the Applications folder greyscale? I think everyone would agree that having a greyscale Dock would be a terrible decision. So please bring back colour to the Finder sidebar (or at least make it an option in System Preferences).
Finder 10.11.4; OS X El Capitan 10.11.6.