My perception as I approach graduating med school (and thus have lots of free time to offer sage advice to strangers) is that I have changed a lot in four years. I was very naive starting out. I tried giving some tours as a 4th year on interview days and I realized that I had a hard time relating to the interviewees. Whereas, when I was a first year, I totally bonded with all of the interviewees. Now, their questions seemed so unimportant. They were so curious about anatomy lab and transcipts and curriculum that I just felt like I wasn't that helpful to them because all of that stuff was so useless to me and any aspect of matching into a residency and finding a specialty career that you would be happy with. The first two years are such a distant blur, its unbelievable. They matter so little its almost as if they didn't even happen. Third year, working with patients, is etched in my head though. That was when med school really started. I feel weathered and older. I swear the number of gray hairs on my head has increased by about tenfold.
Let me qualify it by saying that I went straight from college to med school and I think my experience is somewhat different than someone who took 3 years off before school (which makes me wonder if it really is just the maturing that comes with aging that has contributed to my perceptions changing so much). 3rd year of clinical medicine is a big eye opener. You learn to value life, to respect death, and to never be surprised by the worst. You remember patients' faces that you treated 2 years ago but you don't "feel" for them the way their families do. You "feel" for them the way doctors do, in a wierdly professional, but real way.
I still, if not moreso, believe that it is an honor and a huge responsibility to be a doctor with expectations that far exceed almost any other occupation (except obvious ones like being the president). Its amazing that we are granted the ability, directly or indirectly, to subjectively make definitive decisions that are often morally in debate among the lay community. And our society doesn't agree on them, yet on a day to day basis, doctors wield their power to make these decisions based on their own value system. It is really amazing.
I also believe that there are some doctors that are significantly better than others at being doctors, like exponentially better, and its very obvious if you are on the doctor's side of the door, but very difficult to tell if you are the patient.
In terms of the pre-allo culture...I think people spend way too much time debating prestige and rankings and grades and checklist items for what makes them valuable as a candidate to be a doctor. I now realize that adcoms are a much wiser group than premeds and they usually have a decent idea of who is a stat stuffer and who is the real deal. By the way, there aren't enough "real deals" in my opinion to fill all of the medical schools. Thus, all med schools have a large proportion of stat stuffers. Sometimes, those stat stuffers turn out to be the real deal, but many times they do not.
I think its difficult to predict who will be able to thrive in med school and who won't. I don't mean during the first two years, I mean during the third year when it becomes a combination of stamina, intelligence, diligence, knowledge, people skills, likability, and confidence which make you succeed. Oftentimes, adcoms have their own agendas in terms of who they want and it isn't always the most objective criteria, but I don't think it is something to cry about for premeds. You choose your own destiny, but it is helped by your pedigree and you have little control over that. Get over it and make the most out of what you got. Once you are in medical school, the playing field seems to even out much more. You need to be proactive about your life and career and make success happen for yourself rather than have anybody spoonfeed you the formula to becoming a good candidate for residency. If you are the real deal, the sky is the limit for you. By the way, I don't think more than 20% of my class is the real deal and I'm not sure about myself yet either.
Competition still exists, the culture of med school is far from "laid back" if you are comparing to any normal standard for what is laid back. It is a brutal, grueling grinder of a life. But you start to not feel like there is any other way to live and you laugh at your friends who think that working 50 hour weeks is a tough life. You can't relate to them sometimes and they ask you about med school and you just can't come up with statements that adequately capture what you are going through. So you bond with some classmates and have intense times together (and even more intense post exam parties). You abhor some of your classmates, and are in awe of the talent of others. You feel inadequate for the first time in your life because you just aren't as capable at doing something as someone else is and you've never felt that before. You learn how to stay up for 24 hours straight and it becomes kinda hard but not as ridiculous a notion as it was when you weren't doing it ever. You sometimes feel like its easy and other times wish you were an engineer with a house and a 401K living in the burbs and going to TGIFridays with your buddies for happy hour every night.
But at the end of the day you realize that it was worth it, you would never do it again, but you're glad that you got through it. You feel proud of yourself but remain totally humble that you aren't even close to being where you need to be to treat patients autonomously. And you realize that you just finished something tough but it isn't even close to as tough and stressful as your residency is. Then you feel anxious about getting through the next phase of your painful career choice. But, you're a doctor, nobody can take that away from you. You sign a lease in your new city and feel ecstatic when it asks you what your occupation is and you get to write for the first time...PHYSICIAN.
b/c of the lack of social security 
