At first it may seem that all you're doing is getting into these shapes with a teacher telling you to straighten that leg, breathe and focus but as time goes on you'll see the magic unfold.
The best thing that yoga can do for you (and I'm talking specifically about asana) is get you out of your mind.
Think of your mind as a muscle, the more you use it the stronger it gets. The stronger it gets the more powerful it becomes and before you know it you're running around in there thinking a million more thoughts and never ever present in your body.
Wow, that sounds busy huh. No wonder we have so much mental illness in our world, we are completely over-thinking and not really being present in what is here right now.
So make a commitment to yourself and get out of your head (in the healthy sense) and into your body and breath so you can be present and give your mind some well deserved time off.