You will be pigeonholed into your position and you will never move up.
You only learn proprietary products that you will never use anywhere else, and the IT-related knowledge is as basic as it gets. You will not learn anything that you can use in a future job (which could be good for someone who's lazy).
The culture is extremely cutthroat, plenty of favoritism and most of the employees will stab you in the back, plenty of office gossip as well. Management smiles in your face until they're ready to slit your throat from behind. Beware.
