The art of the film set is the art of the Office Party taken to an intense and much more organized level. I used to think of making a movie like managing a company or a project, and the actual PLANNING is, but the set, on the day of shooting, is really more like that.
Why? Because everyone already knows who they are and what they are supposed to be doing on the day of shooting. The real questions are: Who is going to show up? Will they respect you enough not to walk where they aren't wanted? Is there enough food for everybody?
An office party. Minus the intrigue about who might hook up before the day is done . . . except, no, that's there, too.