Dressing up for work is something I'd love to see studied more. At my first job I wore a suit everyday. Wasn't a biggie except cleaning a bit of a hassle, but I always felt really good going and coming from work.
Now I wear jeans when we have important customers coming by. I definitely like the freedom, but I do think that maybe I should dress it up a bit more. It sometimes just felt really good. Not sure why, or if it matters. Inertia is the main thing holding me back.
Only some days, and rarely now that it's the summer and our office doesn't have AC. Seriously though, I definitely feel a lot better on days I wear a shirt and tie to work, especially since it is a very marked contrast from the rest of Valley culture.