listening

So i was over at a friend's house and i was told more than once that in conversations i tend to listen politely but it's obvious that i am not interested in what is being said. I was pretty surprised to hear it, my friend thought it was funny and i wondered if it were really true. Anyways, that kind of stayed in the back of my mind for a while, then yesterday when my boss was trying to talk to me (longest conversation EVARR) i noticed that my vision kept going in and out of focus because i was trying not to zone out so completely that he'd notice. It would have been comical if i weren't so tired of pretending to listen. Then i remembered what my friend had said and concluded that i really often didn't care all that much about the topic of conversations i'm in.. i feel kinda bad that it's that noticeable when i do it though and ashamed that i do it at all -.- meh.