It's not that you're a little obsessed with your knitting. It's just that you don't see the point of any activity that doesn't involve yarn and needles. You've heard that there are other things people do out there, meaningless, time-wasting things like jogging or playing skittles or getting married. Your only interest is in knitting. So if it's not about that, you don't know and you don't care. Knit on and wear this tee so they'll know just what they can and can't ask you.