Continuity mistake: Josh is getting coffee and talking to another guy about a Shakespeare production Bartlet is supposed to attend. When he goes to the coffee machine, his backpack is over his shoulder and the strap is near his collar but not covering it. When he walks away from the coffee machine, most of his collar is covered and quite dishevelled from the backpack strap. At no time did Josh adjust the backpack.
Continuity mistake: When Josh is walking down the White House hallway in the office area, he is talking to someone, and at first there is nothing in his shirt pocket, but as the scene progresses, we can see his glasses in the pocket. He did not put them there during the scene.