A Jehovah's Witness.
They go off on tangents.
He would be the one with the clean bowling shirt.
They don't like any witnesses.
knock knock knock... excuse me sir, but do you have a few minutes to discuss nothing
Nobody asks, 'who's there ' when you try and tell a knock knock joke.
Someone who knocks on your door at 6 a.m. for no reason.
Cuz freedom rings, baby!
Nothing, because he is the one who knocks.