CO is my secret password

My sister claims I'm addicted to ______. I say I'm not, because an addiction is a compulsive behavior that has a negative impact on your life. She smiles and says, well what you call it then? My CO, I say smiling as well, my current obsession. She laughs and says but aren't you the one who told me they don't obsess hey just think... intensely. I might have been, I say smirking, but this... this is worthy of the word obsession.