1. The General Ledger isn't live. It updates overnight, so you better hope you didn't make a mistake on your journal entries because you won't find out until the next day.
2. Too much is done in excel. Imagine have 50+ excel files (not exaggerating) all linking into each other. Imagine that of those 50+ files some are owned/maintained by other people/departments/etc (even your own files are subject to being changed by another person). Now imagine what happens if one of those other owners decides to add a column or row to one of their files or even delete a cell. You guessed it, everything blows up. Now imagine trying to explain to your manager why your file/files are pulling N/A or Errors when you didn't change anything.
3. Micro management. Even if the boss says they don't care how you perform a task don't believe them. If you do give it the college try, be prepaid to have to re-do everything later.
4. You need to get use to the fact that when you're wrong you're wrong, and when you're right you're wrong.
5. According to some managers, deadlines don't matter (unless it's a deadline that they've created).
6. Backstabbing, in fighting, and throwing people under the bus is common through out all levels (from interns to senior management). One manager even promotes it. With in my first week of employment I was told not to trust anybody (including management). People have intentionally not sent documents on time just to get back at others.
7. Stay far far far away from anything investment department related.