High pressure, massive workloads that are highly unpredictable. You work becomes your life and it is difficult to plan anything outside work. The amount of travel works if you're into it, but if you're a family person the novelty wears thin pretty quickly.
The CEO is a brilliant intellectual and one of the smartest people I have ever met. Yet his inquisitive and insightful mind has a big EQ blind spot. He has been known to bring staff members to tears through conversations that he did not even realise were upsetting to the staff. If you know this, are prepared for it and don't take it to heart, your interactions will be mainly positive and you will learn a lot. He does take an interest in developing his junior staff and makes an effort to mentor them if they're open to it.
Progression within the business and getting a good remuneration package can be tough. Often the business explains a lack of material salary increases by saying that the staff member is gaining valuable experience that will lead to other, higher paid roles outside Castalia. This is undoubtedly true, but it means that there is little incentive to remain for longer than a few years.