Unfair pay-schemes. Older employees make a lot more than newer ones. Some jobs that are essentially the same have different tiers as well. If you get hired as a contractor you make even less. So, there could be a situation in which an employee makes half the hourly wage of another who has the same job.
Aside from the pay inequities, the work environment can be abysmal, depending on where you work. Poor support, and management as well (again, this depends on where you work as with most companies). The schedule is horrid if you work 12 hour rotating shifts. It can be nearly impossible to get time off when you need it. A lot of over-time. On call with no pay for being on call.
No career progression; that is to say, you can progress within the company, but it's extremely competitive and mostly based on seniority and knowing/being related to people in management (or so it would seem). You can come to the company educated, with experience, perform extremely well for years, and essentially stand no chance of getting promoted since there are already so many other employees with more seniority competing for the few opportunities available.
From what I've seen, unless you have an engineering degree, don't expect education to get you anywhere in this company in your first 10 years if you get hired as an operator.
