So much about working here and the opportunities you are afforded has to do with who your friends are. If you're in with the right people, you'll never get in trouble or be held accountable, even by HR. If you're not part of the right group, especially in one particular division on staff, you're not going to advance ever. Employees are allowed to pursue personal vendettas against co-workers they dislike if they're in with the right people.
Finally, and most importantly, as a female, I was unhappy to see inappropriate relationships between supervisors and subordinates and realize no one in power was concerned about things like that. It made me really uncomfortable and unhappy at work. It affects all females at a company, when it is obvious that some female employees are singled out for special treatment because they have close personal relationships with other employees.