Ridiculously long hours
Horrible, HORRIBLE managers - narcissistic, workaholic, weak on social skills, lacking empathy, short term results focused. I found the least qualified managers I have ever encountered in my whole life. One of the reasons why? Because the turnover is too high and thus they simply lose team leaders and have no one to replace them - so they just give the job to the only person they can give it to.
No one listens to you - me and my colleagues presented to the top manager several complaints about our team leader who was rude, mean, borderline sociopath and made our lives a living hell. No one cared.
I felt constant pressure to work late nights, weekends, holidays, you name it. otherwise, I was not being part of the mercer "family" (lol). I had my team manager yelling at me that I should be willing to work all night if I had to, because mercer was more important than my life.
You cannot go on vacations on july and august, because those are months of "peak". Obviously, if you know how to get close to top management, you can go on vacations whenever you want.
Little to no chances to climb up - the paths available are non existent and shady, no one tells you directly and honestly the paths you can take.
Honestly, I could go on for ours. I worked at Mercer for around a year and the day I quit was one of the happiest of my life. I've had several panic attacks, sundays were days full of anxiety just thinking I had to go to mercer the following day. It got ridiculous to a point where you had to send an e-mail to your team when you had to leave work on time!! And they'd usually get really upset about this.
All in all, quiting is the best thing I have ever done. Now I have been working at another place for the last 6 months and It is a huge wave of relief.