Spurred on by my observations at work, I have come up with a list of things to avoid as a doctor in a hospital setting (especially for interns and medical students):
1. Don't wear jeans under your white coat. Its unprofessional, even though it may be more comfortable and convenient.
2. Don't roll up the sleeves of your white coat. You're not a butcher.
3. Don't wear a customised operating theatre cap. You only earn that once you're the boss.
4. Don't drape a stethoscope over your shoulders as a medical student when its clear that you have no idea what to do with it.
5. For the ladies - don't put on lots of makeup and perfume. Especially medical students. I don't worry about the interns, because after a few on-calls they spontaneously eliminate that aspect of their morning routine.
6. Interns - don't spend all day long socialising over cups of coffee. Yes, your existence here is trivial and your job mostly mindless and routine, but that doesn't mean you should be flaunting the fact that you have no work to do. That will just get you into trouble.
7. Do not write short, incomprehensible patient notes. You haven't earned that right just yet. Only the boss can write something he or she only understands and not be criticised for it. Because its HIS/HER patient, not yours you little scoundrel.
8. Don't show up later than your seniors. That may sound like common sense but surprisingly still occurs, requiring a prompt kick up the arse on morning rounds.
9. Do not forget to show the proper respect to anyone who is more senior than you, be it Doctor, Nurse or even orderly. They have been around for much longer than you have, and have seen many junior doctors come and go. You're nothing special.
10. Don't give up on medicine. Even though you may take a lot of abuse, the money and hours are not that great, and the perceived public worth of the physician is ever-diminishing; it can still be a very rewarding profession. Nothing is more fulfilling than helping another human being out when they need it the most. A lot of people go out of their way to do stuff like that for free out of their own time. You get paid to do it, so count yourself lucky.