( Spoilers! ) Cameo?

just saw this the other night--I am very confused by that cameo. I didn't find
it funny, because I don't know what the context is supposed to be, he was acting
quite the jerk to the hotel guy, so in real life was he really a "southern
gentleman" who would NOT raise his voice to anyone ? was he nice and playing mean?
and
I don't get Jerry re-using his nutty professor character here.