When I'm alone, I take my shirt off quite a bit. I also almost took my shirt off running at PE before I remembered that I'm not "allowed" to do that. I wish it wasn't a freaking law in this country.
Also, I will be really happy being able to wear thinner shirts, tank tops, and low cut stuff. I also will be able to breath deep without worrying if people can see my chest rising and falling enough to decide whether or not my chest is moobs, pecs, or boobs and pick boobs. I also won't close my chest as much, but opening it. My shoulders will rest back like they're supposed to.