I'm not saying that you shouldn't have goals and dreams -- you should. That's healthy. But the moment you begin to fixate on that number on the scale, or that perfect hair color, or that ideal clothing size, know that your goals will change the moment you achieve it.
Why? It's because as humans, we're always conditioned to want more. We might think that there's one magical solution to all of our problems, but the truth is that when we find that solution... we simply come up with a new set of problems.
Strive instead of health. Excerise because it feels great, it's good for your body, and it releases endorphins which can lead to greater happiness and clarity of thought. Take joy in your body and all the things it can do. Eat healthy food that you love. Appreciate where you are right now.