As to singers' behavior, yes and no. I find that the better the singer, the better the behavior. The top singers in the business are a breeze to work with. The show up on time, they know their staging, they sign in, they treat their co-workers with respect, they make my life easy. The farther down the totem pole, the worse the behavior (in general). The singers who give me the most problems are the ones who aren't as good as they think they are, who think they should be singing in better companies, or the ones on their way down the ladder, who never got the success they are sure they deserved.
You are working with students, who are still at the stage where they think they know everything, and expect to be treated like stars, even if (especially if) they are only in the chorus, since they obviously should be singing the lead roles instead of that no-talent bootlicker who was cast instead of them.
Apprentice artist are almost as bad, since they are fresh out of college, and are sure that the fact they have made it into a program means they are on their way to the heights.
At the next level, which most singers never get to, they pretty much realize that they are lucky to be singing instead of waiting tables or selling hardware, and they are much easier to work with.
You will soon see that these are very broad generalizations, that most singers are actually pretty good to work with, which is one reason I love opera. But at each level, the bad ones stand out, and at your level, you have more problem children than you need. The good ones, the ones who, from an SM perspective don't exist because we never have to deal with them, are the ones who will succeed and have a career. You'll be seeing them in the future. The problem children? They need to learn an important life skill - how to say "Paper or plastic?"
John