Fans can definitely be tough. And reactionary. The reactionary goes both ways, bad and good. Fans are ready to call a player a bust after a 2 week span, but they are also ready to anoint a player HOF status after a 2 week span. I guess that's the nature of the fanatic.
That being said, I think the majority of the posters here are pretty level headed when it comes to that type of thing. I know I am.
A few of the players like Pedroia, Betts, and Price are going to have to step it up as leaders to make sure that no one on the team is 'rattled' by the fans. I am mostly concerned about Pablo in that area, should he get off to a slow start. The fans will be ruthless.