The porch of Schrute Farms sports a flag that only bears 15 stars. The 15 star flag (which also had 15 stripes) was created in 1795, representing the addition of Vermont and Kentucky to the 13 original colonies. Though more states were added in that time, the flag didn't change again until 1818. Schrute Farms was established in 1812, which puts it right in that historical window. Nobody has changed the flag in over 200 years.

During St. Patrick's Day, Michael puts an Irish flag on his desk to celebrate the occasion. Except, that's actually an Italian flag. The Irish flag is green, white, and orange.

When Dwight finally (temporarily) becomes regional manager, Andy can be seen wearing a short-sleeved shirt in an attempt to emulate his new boss.

In Season Eight, Dwight asks for a new position at the company. Robert California turns him down, offering him a "special" medal instead.

It's an empty gesture. If you look closely in the background at Gabe's office, you can see Gabe ALSO got what looks like the exact same medal.

During the second episode of Season Four, you can see that the whiteboard by Angela's desk hasn't been altered, even though by this time Karen is gone and Ryan has been promoted -- like a real office, nobody at Dunder Mifflin cares enough to change it.

When Dwight makes a tiered chart of his co-workers in Season Four, he writes "Creed Bratton" in quotes, probably because he knows Creed is using a fake name.

In the Season Five episode "The Surplus," Jim brings back Pam some tiramisu from a work lunch; but because they're fighting over whether they should get new chairs or a new copier with the office surplus, Pam dumps the tiramisu in the garbage.

They don't specifically call this out, but later on in the episode, Michael can be seen eating some messy tiramisu -- he got it out of Pam's garbage.

Finally, Michael mentions someone throwing out tiramisu in the episode itself, and the look on Pam's face is priceless -- she knows.

In the Season Seven episode "The Ultimatum," Dunder Mifflin puts together a board of their resolutions.

There are some funny ones in there -- Kelly's is "Get more attention by any means necessary". By far the best one is Stanley's, which reads "Be a better husband and boyfriend".

Dwight puts his glasses on the CPR dummy while he wears it's face

There's probably nothing hidden in this scene, I just love it.