In this construction, obsession has a very specific function: to indicate our special status as the most intense appreciator of this particular thing/work/item. It means I am a fan, a superfan, an intergalactic fan, I am verily defined by this thing, it is my personality, it is me, I am it. What you like (i.e., what you consume; i.e., how you participate in the market) is not just more important than who you are: the two things are one and the same.
