Many have said it in some way or another. Kurt Vonnegut, Xena Warrior Princess, Patrick Rothfuss (who?). We all eventually become what we pretend to be. And it's not just writers and fictional badasses who say so. It's a science thing. Apparently, our brains aren't always completely sure what came first, the behavior or the attitude. In some part of my psychology education, I learned the adage "Attitudes follow behavior." It was tied to that whole cognitive dissonance thing to explain it, but really, the research seems to point to it being a brain chemistry thing.
Smiling makes us happier. Adopting powerful postures makes us feel more confident. If you aren't familiar with Amy Cuddy's work or TedTalk, you've got to check her out.
Nothing is easier to do than these things for just a few minutes every day. In the shower. On the commute. In the bathroom at work. Feeling happier and more confident is in your grasp now. Cool, right? Fake a smile and adopt a confident posture for two minutes. Pretend to be Xena. You will, in fact, be happier and more confident. Yay!
Oh, and congrats! We're almost halfway through the time change. Woot!