A weak point in the plot maybe

Early in the film Red is quick to exit his "graveyard" shift and get out of the diner as soon at possible.
Some time later when Teddy arrives Red is just hanging around for no reason, Obviously Red becomes increasing annoyed by the friendly banter and even jokes directed at him but continues to sit at the bench and wear them. He has ample opportunity to move on but hangs in there to suffer his ultimate humiliation to a point when leaving is not an option. Obviously he is required for the story to play out but the reality is I think Reds character would have long left scene way before things got heated.