1) Your self respect. It is very important to feel proud or happy to work for a company, what it stands for and how they treat and develop their staff. That may not be an essential thing when you have to force yourself over a stepping stone for a limited time. When you consider the job a career choice however it will become a very essential issue that will affect you. When the identification of what you are doing, and why you are doing it lacks over a prolonged time, that's when the personal, professional and social rot will set in.
2) Management and their politics, see above and below.
3) Lack of job security, and union backing due no labour laws
4) Your family and their requirements, ie. school, pollution, lifestyle
5) The long haul grind, deteriorating conditions and having to share layovers with people in the same situation (1-5)
edit: forgot to mention the most important point: missing out on what else is out there!
