There is more to the craft of background extra than one might think. Even though I am relatively new to the craft, I see many who don't take it seriously. Yesterday I worked with a friend. This guy has been doing it for quite a while and has a lot of experience. He is the Bobby DeNiro of background actors. He takes it very seriously, and treats it as a talent. He has no tolerance for those who don't.
While on the set of Memphis Beat, episode four, my friend got into a bit of a yelling match with a man who did not treat being an extra as a job. From the very beginning this amateur was scoffing down the prop food, out of shot in the shade talking on his cell phone. He never was at the same mark twice when he was in the shot. Wandering around talking to people and looking for free Bar-B-Que. Most of the day he spent with his ass sitting on a cooler in the shade gnawing on ribs while telling his friends on the phone that he was an actor.
Bobby DeNiro of extras said they probably hired him to save money. The guy took up the room of five extras when he was in a shot. I said "Yea, but he ate as much as ten during lunch. What they saved in labor, they lost in catering costs." Even when they yelled "CUT" he kept eating. Amateur.