Geeze, I wish that the forum didn't crash so that I could just cut and paste all of the times that I have answered this question. Here you go, in abreviated form:
1. He replaced VDS, I'm not going to go into why and how this is unfair, but it is to me and that is how it is.
2. Everyone says that he is the best, yet he has never played that way.
3. He and Barthez are the only two keepers in the world whom I think are a deteriment to the art of goalkeeping. For them it is a broadway show, for all of the good keepers it is more like firefighting. This is hard to explain, but it makes sense.
4. He does not conduct himself with grace, assurance, or tact.
5. He is the repressentation of Juve's nationalist policies.
6. He is an arrogant, spoiled, inflexible fool.
7. I find his personal appearance and manners distasteful.
8. He is disrespectful to his team-mates, opponents, coaches, and supporters.
9. He wears a short sleave keepers jersey. To me this shows his disrespect for the tradition of minding the nets.
10. He has shown himself to be ignorant and to some extent stupid. This is not something that I admire.
Those are just the top ten.
But I'd rather not this thread turn into a debate about Buffon.