They've booed him the last couple of seasons mate, not because of his form, but they boo him because of his attitude towards his team mates. He was always having a pop at them for no reason, well mainly because he wanted it to all be about him. I watch all the Spanish footy, and I've saw him plenty of times kicking off just because someone never passed to him, even though there was a player in a better position. I remember on one occasion the ball came into the box and one of the Madrid players scored (can't remember who it was) instead of celebrating, Ronaldo through his hands up in the in disgust because the Madrid player never left the ball to go through to Ronaldo (who was behind him) to score. Whilst all the Madrid players celebrated with the goal scorer, Ronaldo just walked up the pitch shaking his head.