I work in an ambulatory clinic that does every surgical procedure including plastic cases.
I don't like to put lump a group of people in a negative way, but it is hard to not notice that the plastic surgery patients are hard to please.
If patients cannot understand the simple, common sense, explanations for why they need to arrive early there is not much you can do.
1) Your safety and an excellent outcome are our primary concern. The nurses and anesthesiologists will do a quick but thorough physical exam. Take your vital signs, listen to heart and lungs, carefully review your chart, medical and surgical history, start your IV, get your vital signs, give any pre-op medications, etc. The surgeon will need to mark your body (probably a better way to say that) to outline where he is going to cut.
2) If you are not the first case of the morning it is unfortunate but possible that your case scheduled to start at 11:00 will start 1/2 (to 1) hour late. Your surgeon will take as much time as he need to do a good job. Unfortunately sometimes that means is he has to, wants to, take an extra, unscheduled, 1/2 hour to do a perfect job. Therefore the next case, will start 1/2 hour later than scheduled. When it is your turn you want the surgeon to take as much time as he needs, even if that means running over a few minutes.
4) And the opposite can happen if you are not the first OR case. Your operation was scheduled to start at 11:00, the case ahead of you was cancelled or finished early. We schedule patients to come in 1 to 1 1/2 hours prior to their start time. We can take you back and get you ready early and start your case earlier than scheduled.