Power
There are lots of times where you're going to feel like a minion: A doctor might treat you like dirt, or an office manager might irrationally dislike you, or a patient going for the Jerk of the Week Award might try to wear you down and make you cry. People will treat you like you're beneath them, because you don't have a super-expensive education or because you're standing between them and the person they really want to talk to: their doctor.
However, there are also times where you, with your friendly, caring disposition, will be able to do more for a patient's peace of mind than the doctor can. There are times when you will serve as a patient's advocate to their physician.
Also, if you can prove that you're a truly incredible medical assistant, you'll always be able to pack up and leave a toxic work situation for greener pastures—that's the power of being a well-respected member of a profession that's in high demand.