When Johnny is at his desk holding the empty bottle of milk, the pen is facing left then right then left again.
The cap of the empty milk bottle alternates between being on the bottle and sitting beside it on the desk between shots.
Even though the producers are quite coy about whether the show takes place in the U. S. or Canada, a Canadian road sign (Speed Limit 50 km/hr zone begins ahead) is clearly visible in the background during the traffic stop scene.