The part about Michael that I never understood was his seemingly negative and aggressive attitude towards Tom,when he was basically brother of his. Why did he remove him as consigliere in favor of non-family member Carlo before the move to Nevada when Tom had been Vito's consigliere in Part 1? Why does he later aggressively dig up dirt on him and ask if he was going to go along with the things he had to do in Part 2?