I can't believe I have to explain this for the 1 millionth time on this board.
In order to "quit", you have to be an active participant, that is the basic Webster's definition.
We all here, including you my friend, are spectators. Again, consult Webster and you will see that a spectator is simply an "observer of an event".
Thus, a spectator (a fan) cannot quit on their favorite sports team because they are not an active participant. They can cease observing (turn the TV off or leave the stadium), but that is in no way shape or form quitting, they just simply stopped observing.
Just had to chime in, I am a stickler for using words correctly, sorry.