1. It turns out there might be a real reason Pam doesn't want the camera crew to call her "Pammy."
2. Right next to the pathetic little bed where Michael Scott sleeps, there's a George Foreman grill.
3. In every episode with the Michael Scott Paper Company, Michael has a new fish in his bowl — he probably wasn't very good at taking care of them.
4. Karen's Call of Duty name is "KarentheJimSlayer."
5. When Michael visits the Utica branch in "Lecture Circuit," the copier is padlocked to the wall and there's a sign that reads "Report any suspicious activity near the copier." The last time he was in Utica, he and Dwight tried to steal said copier.
6. The funeral home guy at the job fair actually makes a very subtle cameo the next season.
7. David Wallace has a "World's Best Boss" mug on his desk, too.
8. Gabe is so tall that he had to stitch two skeleton costumes together for Halloween.
9. Kevin's desk area had an important little reminder fixed to the wall.
10. Ever notice how Michael says "grilled bacon" in "Lazy Scranton," even though bacon is usually fried? Sounds like a subtle nod to his George Foreman bacon ritual!
11. When Oscar realizes that Kevin can only do math when it's about pie, he gives him an equation where the answer is "314." That's pretty much pi — 3.14!
12. Pam's insistence that she doesn't want to marry Roy on the booze cruise ends up coming full circle at her wedding to Jim.
13. Creed wears a tie, jacket, and sweatpants in one episode, and nobody seems to notice.
14. When Creed and Robert California have a "jinx" moment, Creed says, "Jinx, buy me some coke." He doesn't want Coca-Cola, kiddos!
15. Dunder Mifflin's St. Patrick's Day celebrations were more festive than you realized.
16. In later seasons of the show, Dwight is growing a beet right at his desk.
17. Phyllis and Bob's wedding cake topper had a little refrigerator on it — and they had a cake made to look like a refrigerator, too!
18. The Michael Scott Paper Company had clocks for time zones all around the world, and apparently Michael thinks "USA" is a singular time zone.
19. During Michael's apology video in "Product Recall," Dwight holds up a cue card with a statement that reveals just how bad Michael is at managing his money.
20. In Michael's movie, Threat Level Midnight, the exterior shot of Scarn Manor is actually a real estate brochure from his ex-girlfriend, Carole Stills.
21. And finally, while setting up for the Finer Things Club, Pam brings out ~the teapot~ Jim gave her for Christmas in Season 2. Cute!!!
H/t to r/DunderMifflin.