As someone who moved to the US at a young age, reading How to Make Friends and Influence People explained a lot of the apparent insincerity/fakeness that bothered me in both business and personal interactions, and that had been very much a mystery to me.

How did that go again?

   Dear $FIRSTNAME $LASTNAME,

   I am writing you to emphasise how much your business personally means to me and how $EMOTIONAL_STATE I feel about it...

Also remember that he was a huckster, for example changing his name so people would associate him with the steel Carnegies (no relation).