Michael's goatee disappears in a lunchroom scene and returns for a weigh in. He later shaves it off.
When Andy changes the thermostat to provide an "old-fashioned sweat lodge", it is shown to be an old, brown box. In Dwight's Speech (2006), members of the office are seen in a battle over changing the temperature and the thermostat is a more modern, circular dial.
When Pam goes to her first class and the instructor slides open the whiteboard to show the name of the course and her name, the word "professor" is misspelled as "proffessor".
Pam comments to Jim at the gas station that: "Montclair would have been closer, so you have to buy lunch". This is untrue. Montclair, NJ, is 1 hour/ 50 minutes away from Scranton, PA (Jim) - but only 55 minutes from midtown Manhattan (Pam). That is not at all halfway between the two locations. Newton, NJ, would have been a better compromise.
Pam announces she's going to attend the Pratt Institute in New York and then says, "What up, 212?" Pratt is in Brooklyn and the area code is 718.