1. Cutthroat work environment, do not trust your managers, they will cut you down to get a promotion at any point. I agree with the other person who said they wear masks.
2. Poor cohesion between teams, since everyone is cutting each other down to get higher.
3. Everyone will seem nice until you are hired, then you will understand the real work culture.
4. I have worked at 3+ jobs in my life, including fast food. This was significantly worse than any of them, you are barely treated like a human.