The lady in the wheelchair, behind Diane, comes out of nowhere, within seconds of panning from Diane to Norm and back to Diane.
When Norm say the line to Sam, "Maybe you are drinking a little more than you should", he has an empty beer glass. The scene cuts to Sam momentarily then back to Norm where he now has a full glass of beer.
An old lady customer is seated in a wheelchair; no one else is with her, and she could not have gotten down the stairs to the bar by herself.
When discussing the Patriots draft pick, they say they took a linebacker with the first pick. In fact their first pick was a Defensive End, and their other first round pick was a Defensive Tackle.
When Sumner goes to the back to make a phone call, a crew member can be seen sitting on a wooden chair with a camera beside him, as can a few more people in the distance.
There is a reflection of a studio light in a large glass picture frame on the wall behind Norm.