Most important person in Lincoln's life

[Angela]

What a great topic!

I would like to add to the growing list David Davis who met Lincoln right after his return from his time in congress and they quickly developed a deep and lasting friendship.
While from very different backgrounds, Lincoln and Davis spend a lot of time together on the 8th judicial circuit and it was during that time that Lincoln really developed as a politician as well as a lawyer.

Davis was known to appoint Lincoln to sit in as judge in Davis’ absence and he became a very close counselor during Lincoln’s later political campaigns…all the way to his nomination and election for President.
Given Lincoln’s track record in Congress and his subsequent development, I can’t help but speculate that it was Davis who taught Lincoln some tricks of the trade.

As for Mary Lincoln (and I have to apologize in advance for being the one with the unpopular opinion), I completely fail to see how she influenced his character. She might have influenced some of his decisions (which I’d think normal in a marriage) as for example the move to Oregon. But both, the biography of Nicolay and Hay as well as Noah Brooks writings, indicate that she simply did not want to move to “the wilderness”.

Her attempts to influence his political views (e.g. Seward, Grant) were fruitless as was her idea of dressing him up.
He was known to greet visitors in socks back in Springfield and found looking just like this when greeting visitors as President. His string-fixed glasses as well as his trademark clothing style indicate the same. They might have agreed on certain topics – like on how to raise children – but I don’t think he needed much character building on this end.
He never caught up on her lifestyle ("Mrs. President") but rather enjoyed being one of the many without much fanfare made about his person.

And - and this is TOTALLY tongue in cheek! - while Mrs. Lincoln might have taught him "to see color", Frederick Douglass sure pointed out how much he enjoyed that Lincoln seemed to have forgotten it when talking to him.