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I think Tom knew Michael was cruel, in a way neither the Don nor Sonny were, and as such, feared him - Or what he COULD do.


I think this is right, though I think "cold" might be more precise. It all runs back into the novel - Michael the mathematics professor, the rationalist. Kay loved him because he was "always fair," but she didn't realize his fairness could turn him against you if you failed him, and that everyone would fail him eventually.

"All of these men were good listeners; patient men."