Unity doesn't load, no Launcher, no Dash appears
Unity seems to have broken itself!
I logged out of a Unity session and logged back into a GNOME/Openbox session to try out the GNOME Shell.
I logged in however, the Gnome Shell didn't seem to start up, and I was left literally staring at my desktop wallpaper.
I rebooted my laptop and logged in back into a regular Ubuntu session. However, instead of Unity starting up, the only desktop environment I get is my desktop wallpaper with a menu bar running along the top.
No tray, no unity launcher, no lenses, nothing. What went wrong here? How can I get my Unity working again? And how can I try out Gnome Shell without seemingly breaking my Ubuntu installation?