why are you listening to hard rock music?

I love living in close proximity to people who are not your family, but you treat them as such... aka roommates.  For example, this morning I got up around 9am which is early for me.  I stumble in my underwears to the kitchen to make myself a coffee.  I hear what seems to be loud rock music coming from Jon's open door.  This conversation follows:

Me: Why are you listening to hard rock music? (in a grumbly morning voice)

Jon: (peeking out of his room whilst dressing) It's Something Corporate...

Me: Oh, sounds like rock to me.

Jon: You're an idiot.

Jon and I are in no way related... except one time we told an entire party that we were step brother and sister.  His dad married my mom in a romantic Brady Bunch way.  They believed us and it became a disaster from there on out. ANNNYYWAY... Jon and I are not related. But, we were facing each other in the early morning light in our underwear arguing about Something Corporate.  And I thought to myself as I poured my coffee, "Is this real life?" 

Is this how roommates normally interact?  This may not seem weird to anyone else, but I think standing in underwear talking to your roommate is so ridiculous.  I mean granted, it is a home and therefore you are allowed to do what you please (within reason), but it just seems funny to me that underwear interaction is so common and just a shrug of the shoulders.

It is completely my fault.  I think Jon and I are the only ones who do it, so it is natural that we chat in our underwear.  But, listening to "I Kissed a Drunk Girl" at 9am while in your underwear?  It just seems to me that this is behavior for a) a married couple who need to find a new band b) a brother/sister combo c) boyfriend/girlfriend combo... 

Maybe we are breaking down walls here.  Starting a new era of roommate comfortability? We shall see. ROOMMATES EVERYWHERE HERE THIS: UNDERWEAR IS OKAY!