You know, when you get that scenario with the perfect set of affixes for that one hero. I've experienced a few really good ones, but the most satisfying was a recent cosmic DR with Endurance, Physical Damage Bonus and Damage Amplification Zones - played as Colossus.
I still grin when I remember the fun of the (very brief) final fight against duplicate Kingpins; jumping into the middle of the damage amp circle, firing off his ultimate, followed by an 18 million damage signature, followed up with auto-brutal haymakers powered by 175k or so of health. I was almost disappointed the fight ended so quickly. ;)
Anyone else have stories of any crushingly unfair (to the enemies) Danger Room combinations to share?