shoes and socks

Karen:  What shoes are you wearing?
Susan:  My new ones, why?
k:  I was going to wear them if you weren't.
s:  oh, you can.  I'll wear my black ones
k:  no, no.  I was only going to wear them if you didn't
s:  no big deal, you wear them.
(a few minutes later in the car)
s:  I hope you're enjoying those shoes, cause I have white socks on with black shoes
k:  Um, maybe we should switch socks...  (pulls up pant leg, to show gray and black trouser socks.)
s:  No way, my feet were cold all day yesterday, and I wore thick socks to stay warm.  Besides, I am a sharer, and I have shared my shoes, damn it!
k:  So you're selfish about socks, then.
s:  Well, technically, these are your socks too.
(pensive silence)