The one thing in this entire thread that I feel a need to comment on is someone saying that if a crew member can't take the heat, then they must be in the wrong job.
It doen't matter who you are, or what job you are in, if the conditions are unbearable for the person, then they are unbearable. Everyone has their own limit as to how much they can put up with, but this can happen to anyone in any type of job. If a person has to leave a job because of poor treatment, then that is not right. It has nothing to do with the person choosing the wrong type of work.
This is not to say they people always choose a career that is right for them. There are many reasons a person might end up in the wrong job, but that is not what this conversation is about.