Banned for fighting Galactus without the aid of the Silver Surfer.

Your girlfriend left a note on the fridge. It said, “It’s not working. I can’t take it anymore. I’m going to my mom’s.”

You opened the fridge door, the light came on, and the beer was cold.

EDIT for the real reason...

banned, for not understanding what she meant

Banned for confusing the Thing with the Thing; confusing it for the Thing is a lot more reasonable. As crazy as it sounds, there's a correct way to guess which Thing is which in this statement.