I think I’ve met a few of these in my days.

curmudgeon (cur·mudg·eon): / ker MUHJ uhn /
noun

(1) a bad-tempered, irritable, disagreeable, cantankerous, stubborn person, especially an old man

[Etymology unknown. Perhaps originally used to suggest the sound of grumbling.]

Usage: What a bossy curmudgeon he was, always brandishing his opinions as though it was impossible for him to be wrong and others to be right.