Can you choose your mood?

I really like this website. I've read some really terrible stories. I've read some really uplifting quotes and messages. Do you think you can choose to be positive and happy? Yesterday I felt down in the dumps a bit. BUT, I chose to pull myself up and out of it. I had a great evening last night with my family. This morning I was up for my 5am run. I did it. I'm choosing to have a great day. Nothing will bring me down. I want others to be able to choose to be positive and happy today. There is always someone out there that is worse off than you. No matter who you are, you have things to be thankful for.