It saps the life out of me, I know football has changed but I do not understand the mentality of coming to a game purely on the basis you are going to tear every inch of the team and club you "support" apart.
I really really REALLY do not understand jeering one of your own players being taken off, I find it disgraceful, and don't tell me "I pay my money I pay his wages", its just an excuse to be a prat. Not only that in what I believe should be siege mentality against the other club, on and off the pitch, what message does it send to the oppo? If they are giving our players **** and we are doing it more than them???? And people truly wonder why the team is sometimes nervous at home, there is an element of human nature to the game.
I think of it this way - You think about how effective a positive crowd are on a teams performance and then turn it on its head and think how much impact a negative crowd has, its huge either way.