Infinite Loop with no (fair) way out
Situation: I had an infinite loop with Marauding Blight Priest and Exquisite Blood; opponent had Pact Weapon attached to a creature. Hence they could not loose even with negative life and the combo went on forever without anyone being able to stop it (other than one of us conceding, which doesn't seem fair). After about 20 min of watching in morbid fascination my computer finally crashed when I was at ca. 1200 life and they at ca. -400 life. I guess it comes down to stubbornness and good hardware.
The irony was the displayed text on the battlefield: "Warning: Please take a different action or the game will end in a draw. " (WHICH WAS NOT POSSIBLE)
No ****. A draw would have been fair and totally fine by me. ONLY THERE WAS NO WAY TO END IN A DRAW (or even just stop the loop). Please add a way to agree to a draw, when there is a catch-22 like this or have the game do it automatically after a certain time.