Micromanagement, office politics, favoritism, employee incompetence, etc..
Worked hard for years, surpassing my fellow coworkers in skill and level of effort. Never received more than a marginal raise (%2 which barely keeps up with inflation).
They used to offer an $80 phone allowance and $60 internet allowance. This benefit was taken away ($1680/Yearly Salary Reduction) in the same stroke they raised health benefit premiums.
When I put in my two weeks in, they cut it short as to not pay me a holiday during my last two weeks. Lesson learned, DO NOT GIVE AUSGAR a 2 week notice, you are better off just quitting the day before you start your new job as not to give them a chance to screw you.
In my last year here I saw several good employees get fired for no reason.