He once made Lincoln wait in his parlor for an hour then sent his wife down to tell Lincoln he had gone to bed and couldn’t see him. An officer who does that to his commander should be sacked immediately. Lincoln’s cabinet urged him to fire McClellan for that insult. Lincoln put the country ahead of his own pride and did nothing, believing Mac was the only officer he had to lead the troops.
I remember reading about that specific episode with McClellan, and wondering why Lincoln tolerated his insolence. I’ve never heard what McClellan’s relationship was with Stanton. I know Stanton didn’t have a very high opinion of Lincoln early on, but as the war progressed, he came to admire and respect him.