This has become even easier now there's a proper-shiny, free in-browser version of id's medium-defining dumbass shooter.
In case of grumpy, old-man-y emergency: fire up the game.
There is nowhere in my house from which I cannot reach Doom within a matter of seconds, be it on my PC, my 360, my hacked iPhone. To this end, I am diligently ensuring I'm able to play the thing anywhere and anywhen.
While adult-me might have baulked at Killing Floor's testosteronal presentation, I still revert gladly back to dumb little teenage-me whenever I play the original Doom.