My sweatpants, t-shirt, and shoes with socks let me roll a D20 for a saving throw when I mess up instead of a D3. I like my clothes. 
lol sounds like a d&d reference to me! lol -nerd talk time- i wear my +5 shoes of dexterity everywhere, so if i were to practice parkour naked, id still prolly wear my shoes, JUST because i havnt adapted my feet to "natural" running. so in a sense if i went nude&barefoot id be rolling reflex saves, will saves, AND i'd lose my incredibly high dexterity bonus! -/nerd talk time-
ok im done
so in normal sense, we'd be streaking through town, wearing nuthin but shoes, (or nuthin at all for some)