It really is the best when he does the full “hey, c’mon, man,” but this is pretty darned close. I think even the Left cringes at it.
It’s a coping mechanism not unlike Kamala’s Joker laugh. He does “c’mon man” when confronted with something that could embarrass him; she deploys the Joker laugh when faced with a situation or question she is too stupid to understand.
Those are definite tells.
I grew up in DE and Joe Biden was my Senator until we moved.
That is an very old tell.