Management lied to me. They said I would have a salary re-evaluation at my 90 day mark. It didn't happen for over 6 months. And even when it did happen the raise I got wasn't what I was expecting for the level of effort and impact I had been putting in.
Long hours. Especially around March/April of every year there are very long hours you'll need to work to get stuff done.
Understaffed. They couldn't fill the needed positions quick enough for all the work they had to do. I felt very overwhelmed the whole time. Several weeks of 60 hours.
Poor judgement. They asked for the $5000 sign-on bonus back because I quit before a year working there despite the fact that I played a crucial role in them renewing a very large contract that kept their business going.