This is the ultimate, no-nonsense, hardcore exit command for the worst-case scenarios of exiting Vim if you want out, have no idea what you've done and you don't care what will happen to the files you opened.
Ctrl-cEnterCtrl-\Ctrl-nEnter:qa!Enter
This will get you out most of the time. Most.
SomeYou might think, naively, that you can just bang Esc a few times and then do :qa!. Oh, how you would be mistaken.
See these interesting cases where you need something like thishitting Esc is not enough:
iCtrl-ovg(you enter insert mode, then visual mode and then operator pending mode)QappendEnteriCtrl-ogQCtrl-r=Ctrl-k (thanks to porges for this case)iCtrl-ogQCtrl-r=inputdialog('foo','bar')Enter:set insertmode(this is a case when Ctrl-\Ctrl-n returns you to normal mode)
This answer was corrected due to cases above. It used to be:
EscEscEsc:qa!Enter
However, that doesn't work if you have entered Ex mode. In that case you would need to do:
viEnter:qa!Enter
So a complete command for "I don't want to know what I've done and I don't want to save anything, I just want out now!" would be
viEnterEscEscEsc:qa!Enter