If you are mono-blue or mono-white, there is a good chance that you have done something to earn a Boil or Flashfires every now and again. It's your friends' (if you haven't driven them all away) special way of telling you to stop being a spike-douche around the kitchen table. I have Boil in my five-colour EDH. It will sit in my hand, waiting for some prick to try to combo out on a Time Stretch, or something. Goodbye, islands. Hope you had a backup plan. 5/5 for griefing a colour that well and truly deserves it.