Ask HN: What do you wish you had known before you took a new job?

I have a friend looking at a job offer and we were talking about the question of hindsight. She is thinking about taking a new position and is wondering what you wish you had known/discovered about your employer before you took the job?

What do you wish you had known about the company you were working for prior to working there?

What do you wish you had discovered about your current employer before you were hired?

Any questions you wish you had asked or processes you wish you had known about?

Thanks!