Dressed or Undressed?

So this morning I was in the bathroom drying my hair when I heard a 'knock knock knock' on the door. I opened the door and what did I see? My roommate standing in the hallway in his boxer shorts and only his boxer shorts. He asked how long I was going to be in the bathroom, and then disappeared back into his room. I thought the whole thing a little strange since a) I had just seen my roommate in his underwear, and b) he didn't seem to be bothered by that.

That got me thinking about things and I remembered a time when one of my boyfriends went out on the balcony to hang up his towel in just his underwear. To me that was a bit strange, but he just replied "It's not like I was naked or anything." Fair enough I suppose.

For my part, I would not go walking around my apartment in my bra and underwear, nor go out on the balcony dressed as such either. It seems that guys consider themselves 'dressed' in only underwear, while I consider myself rather 'undressed' if I'm only wearing underwear.

Is this a guy thing, a girl thing, or only a me thing? Any thoughts?