A photoshoot is a high stress situation that can often push emotions to their limits, and lead to conflict that can tear a great shoot to pieces. Part of your job, as the photographer, is to captain the shoot in a way to avoid this sort of thing. Everyone has a responsibility to be professional throughout the shoot but it is you who must ensure that they adhere to this.
Never Reveal Your Frustration
During a shoot everyone is taking their queues from you. You need to become adept at always seeming calm, cool, and collected even if, on the inside, you are a raging torment of anger. Learn to act cool. If something isn't working just keep shooting, cheerfully, while you problem solve in your head. If someone's ego is getting out of control confidently pull them back in line or calmly ask them to leave the set. Never reveal that you are struggling because if you seem stresses everyone else will become stressed.
Check Your Ego at the Door
I don't care how "good" you think you are, an overinflated ego is always a recipe for drama during a shoot. Drama that is your fault. We have all seen the cliche photographer in movies and TV that is so obnoxiously full of themselves that it would be impossible to work with them in the real world. Don't be that photographer. Some tension on set can be useful to coax great expression out of your model but if everyone around you hates you, they are going to begin jumping at every chance to create conflict.
Hungry People Are Cranky People
Be prepared to ensure that everyone on your set remains hunger (and thirst) free for the duration of the shoot. While I'd agree it is the responsibility of each individual to feed themselves before showing up, I've come to realize that many don't bother. As hunger begins to set in patience heads out. Don't let an otherwise great shoot be ruined because someone's stomach is growling.
A photographer must take on the role of the conductor for their own shoot. Any sort of problems that happen during the shoot are your responsibility to be prepared for and to handle accordingly. The best photographers know how to keep everyone working together in a positive way by keeping their set clear of drama. Take steps to ensure you are one of those photographers.