Specifically to prevent you from winning when you're about to win.
Dave: You can't place a tile on the board John: Why not, we've been doing that the whole game?
Dave: Bitch please, It says it right here in the rule book.
John: Brodigans!
T: Wow, that chick can simultaneously sing, juggle with one hand and perform complex mathematical equations with the other hand. She must be some kind of prodigy!
B: Nah man, she's not a prodigy, she's a 'broadigy'!