So many of us can relate to the all-too-common scenario of wanting to get in shape, feeling the motivation and doing your best ... but feeling after a while that something's just not working. You don't feel as good as you'd hoped. You don't look as good as you'd imagined you would. So we end up getting disappointed and discouraged. Motivation sink and the gym membership card gets buried in the back of our wallets and we're right back to where we started. It's why gym memberships spike in January but gyms are relatively quiet come March. You can't rely solely on will power to help you succeed. Here are six ways so many good intentions let you down and how to fix them to work for you.