Basically just mirroing what was stated, but to elaborate on my previous comment:
When it comes to subspecialty training, numbers basically demonstrate whether or not you should even be considered for a spot. Do poorly, and you get shuffled to the bottom of the stack. Do well, and you're at the top. When you look at the people on the top, their numbers are pretty similar. They're all top of the class, they all have high scores, and within a few points on their respective exams they all look pretty similar. That's when personality and other accomplishments come into play. If you don't get along with the residents during your rotation, or you do something stupid like make an ass out of yourself drinking, etc., etc., then you'll get tossed out of the stack. It is subjective, but a part of the progam director's job is to make sure that things run smoothly. One very straightforward way to do that is to make sure that the residents jive. And you don't want to spend 3-7 years working with someone who is a weirdo, or who you can't trust to take care of business. Numbers do not reflect those qualities very well. Numbers just tell a program director whether or not to consider you in th first place.
In the end, if it's a good year, a residency will end up with a list of 5+ students that are high scoring and good, trustworthy people. Then it comes down to the match. In a bad year, you might have one student you like, and a handful of maybes or even a guy you don't really like but you still have to rank. There have been years in which certain subspecialties have just enough or not enough applicants. There have been other years in whic a lot of people don't make the cut. You never can predict it.
So in terms of scores, do as well as you can. Even if you think you will want to end up in family medicine, shoot for a high score - because you never know, and you want to keep your options open. When you are rotating through potential residency spots, hang out with the residents. Get an idea of what kind of people they are, and whether you think you'll get along with them. If you think you could hand out with them personally, then it's a good match. And if you have those high scores backing you up, your chances are good.