Definitely meant this as a joke. But for the context you're wanting:
Our playgroup plays cube in teams (4 vs 4). We draft individually and then the teams work together during deckbuilding, helping each other, discussing strategy, etc. The we play out four matches versus each other person on the other team, and the team with the best combined record "wins" the draft.
In the six months we drafted weekly with Elspeth, Knight Errant in cube (a power-maxy cube), I don't remember a single time where she wasn't on the winning team. It's partially because the best player (not me, by a far cry) in our group has an unreasonable love for Bitterblossom, Lingering Souls, and Elspeth, partially because those cubes suffer the "Junk" problem where there are so many value creatures in those colors and Elspeth just makes them better, and partially because Elspeth is actually super powerful on an empty or near-empty board.
But who cares about winning, or losing, or teams? The point of this rambling is to tell the story of the worst game of magic I've ever played. It was round 1, and I had drafted a BW deck with Elsepth, Lingering Souls, and wraths. My opponent was in Junk. We shuffled up and played the first few turns like normal magic players would, trading resources, casting spells, etc. Then Elspeth hit the table, followed by Day of Judgement, Wrath of God. The game drags on sevral more turns, Elspeth ticking up all the while, but my opponent has built a large board state, thanks to Deranged Hermit, Cloudgoat Ranger, and Revilark. I had a sizeable defense, thanks to the Soliders. At some point during this mess, I make an Elspeth emblem so all my dudes were indestructable. The game dragged on through this stalemate for way-too-many more turns. He had some way to gain a bunch of life and continued to make tokens. We were hellbent thanks to Lilianna joining the party. We got to a point where we realized we didn't want to play Magic anymore, because the game was such a stalemate. We counted cards in libraries (for decking out) and they were even. So we conceded to each other, both took losses, and shuffled our decks back into the cube. There was just something about that particular game that was... miserable.
So in my mind, when I see GRBS, (which, yes, stands for "Game Ruining Bullshit") I think of Elspeth, at least in cube.