Most of us taking the mcat are also ambitious, intelligent, good test takers (whatever the hell that means), and have studied for a long time in preparation of the exam.
Still, some of us are going to make 20's. The mcat is a test that smart people do poorly on.
In fact, most people who retake the test with a high score (36-38, there isn't data on people who retake with 40+ since nobody retakes if you have a 40+) lower score. So, in all likelyhood, even people who make 40+ probably can't make a 40+ on the mcat. If anybody with that score wants to prove me wrong, go right ahead and retake the test. I'll admit I'm wrong if you're willing to risk it.
And seriously, you'll never look back and care that you made a 40 on the mcat. It may seem glorious now, but in just a few years you'll be more concerned with your USMLE scores and won't give a crap about it. I mean, how many people here say anything about their SAT scores?