You do have the power to make people feel good—hopefully that'll be enough for you. There aren't very many massage therapists in leadership positions, and if there happens to be one, then they're likely there for reasons other than their ability to loosen your lower lumbar.
On the table it's a completely different story. Your clients may be paying for the service, but you're the one who knows the difference between a Swedish and Shiatsu massage. You took the training and learned the techniques, and they have to just trust and lie still while you go to work.
Of course, if they don't like what you do—or more importantly, how you do it—a client can always easily switch to another provider. Customer service with a smile will take you far in this career. If you're not a people person, you might want to consider finding another gig; you may be great with your hands, but if your heart isn't in it, your client may seek out someone who actually cares.
So take a deep breath, fall gently into the music, and make sure your clients are diggin' what you're sellin'.