1) No set work hours
Some advisors will request/highly recommend you be on campus a set time. However, you'll be able be flexible with these, as long as you still get your work done. 40 hr week? 80 hr week? 20 hr week?
2) Content content content
You're in charge of making things. Experiments. Papers. Equipment. Teaching. Protocols.
3) Work remotely
Did someone say coffee shop? Camping? From your lab...ok fine, your desk.
4) Product Development
Papers, dissertation or thesis. You're working through multiple iterations of a 'product' during your degree. Refining and honing your project until it's finally 'ready'.
5) You prosper when you create
If you're not hitting goals and objectives, don't expect to do well here. You're creating things! Constantly. You're job as a PhD student is to make things and have people critique them
6) Set your work-life balance
Much like # 1, but I wanted to draw it out a bit more. If you need to make a better balance for a while, you can. You have to power to set your priorities and change them as you need
7) You have investors!!
Your advisor. Committee. Department. Funding sources. All are taking a stake in you and your future. You'll be meeting their expectations and required to listen to their input on your project...because they're the ones footing the bill.