If you hated Ubuntu's Unity desktop then the shock of your first encounter with the Gnome-shell likely caused your entire digital weltanschauung to implode. Make no mistake about it, it takes you right out of your comfort zone to a strange and unfamiliar place even if you've already tried Unity and decided to throw it back or put it in the keep net. Be shocked, very shocked.
There are few certainties in life. Death, taxes and Microsoft FUD are three of them—and the fact that, sooner or later, upgrading Firefox is going to break one or more of your killer extensions.