Yessiree Bob is a historical figure from the late 1800s who traveled way out West to seek his fortune and he got this moniker because he suffered from a rare and devastating brain disorder which caused him to answer in the affirmative whenever he was asked a question and this led to his downfall in business when he was defrauded numerous times because of his inability to utter the simple word, “no.”
Yessiree Bob, there he goes without a nickel to his name or a place to lay his tired head.
A discombobulated form of "yes, sir" and sometimes spoken as "yesiree-bob." However, no one knows who this "Bob" person is, nor why his name is not capitalized, and whether or not a comma should have been added before his name. Sounds haphazard.
"Yesiree, Bob! I slam-dunkin' agree with you, bro! " soon becoming the lazier usage, "yesiree-bob!"