Doug spills fried rice all over himself when he slams on the brakes. It has completely disappeared when he gets out of the truck.
When Doug does the crossword puzzle, he starts to write on it. In the next shot he holds the pencil still, away from the paper.
When Glen guesses that dinner was chicken, he starts to smile. In the next shot, he is frowning again.
When Doug first sees the chicken in the road, its head is tucked out of sight. In the next shot, the head is completely in view.
During the meeting at Ultra Burger, there is a Styrofoam cup near the man with the suspenders. In one shot the cup is tipped over, while in all others it is standing up.
They say Doug became a vegetarian, but he would not eat seafood nor dairy which would make him a vegan not a vegetarian. Vegans don't eat any animal with a face, nor any seafood, nor anything from an animal meaning diary products while most vegetarians do eat dairy products. A special type of vegetarian -like person does eat seafood but they are called pescetarians.
As Doug is carrying the package around town, it is quite obvious that he is in California, not New York. Various indicators include palm trees, a building that says Pacific Alliance on it (next to those palm trees), and red painting on a curb to indicate "no parking" (New York uses No Parking signs).