Why they invest years into an employee and an employee invests years with them and when the employee hits a certain salary they dangle promotions and raises in front of your face like a carrot but NEVER go through with any of it. There is always a glitch or a catch and you are never paid what your worth. At a point instead of giving you a raise and keeping you happy they treat you so badly you leave or HR is really good at making up reasons to fire people and calling it a "company violation".