How managing your energy is key to performance

Think about yourself for a moment; you started your day ready to take on the world. From the moment you got out of bed, you've been thinking about all the things you're going to get done today. You can't wait to get started!

Then it all falls apart.

By the end of the day, you're grumpy and out of sorts. The day somehow derailed, and here you are, feeling like you didn't accomplish half the things you wanted to do today. What happened and how can you change it?