Is happiness a choice?

I've managed to form quite a routine since I began my summer school schedule, one that involves going to bed and waking up at same time every day, something I hadn't been able to do in my first 5 months here. Although it was nice to have a bit of a variation in schedule, it's definitely true what they say about your body being happier if you get the same amount of sleep every night.
Part of my morning routine gets me to the Metro just in time to grab a Publimetro, one of the free newspaper publications that they hand out every morning. I usually go straight to my horoscope, peruse the remaining contents for awhile, and then take it home to Ita who then reads it cover to cover every afternoon.
This morning's edition is dedicated to happiness, more specifically about taking control and learning how to be happy. It also features a brief interview with Gretchen Rubin, the author of a book called The Happiness Project, which now appears to be published in several different languages. I actually read this book over the summer before I left for Chile, and although I didn't start my own project, I focused on the underlying theme that is present in many books of this nature, the idea that we are partially responsible for creating just how happy we actually are. In order to change our level of happiness, we have to change something.
Many of us fall victim to the circumstances of our lives. In saying this I'm not referring to those people who are truly suffering with a horrible disease or who have experienced something really tragic. I mean the people who get caught up in their daily lives without ever really taking the time to think about what's important to them or if they even like what they're doing. I had started to become one of those people, and indirectly that's what brought me here to Chile. I just needed a change...
I wanted to get away from my American lifestyle of going through the motions and killing time by buying more stuff at Target. I didn't give away everything I own, but simply due to space limitations I am living a much more simplistic life on a wage that's about half of what I was making at home. It's not having less stuff that has made a difference, it's what I've done to fill the space that has sparked the change. I don't drive, shop, or watch a lot of TV. That alone has freed up time to ride my bike, practice more yoga, read, journal, walk, improve my Spanish, etc. My friends Amie and Bryan are making similar plans for their own lives, and Bryan writes beautifully about minimalism here.
I know that many of my friends at home don't have the option to spend this much time on "themselves". They have busy lives, small children, work, and other responsibilities that bring them stress. The author of this book was in a similar situation with her own busy life and small children, but over the course of a year she managed to make very small changes and saw significant results.
What's something very small in your own life that you could change that would bring you greater happiness? Not a resolution, not a diet, not a pledge to give up Diet Coke...think about it. Pick up Gretchen's book, check out her website, or start making your own list. It could be something really small like pledging to have dinner with your family at the table every night. It's still January people, the perfect time to start.