In a study being published in the journal Psychological Science, scientists say they figured out why overhearing a cellphone conversation is so annoying. No, it’s not because talking on a cell phone makes people think whoever’s on the other end suddenly went deaf and they need to shout. And no, it’s not because you don’t need to hear the gory details about their sex life, morning after, or recent operation. It turns out it’s because when our brain only hears half of a conversation it tries to fill in the other side, sucking up more of our attention and concentration than if we hear both sides of a conversation. Thus, it’s more distracting and harder to tune it out. And more annoying. So the next time someone’s sitting near you talking loudly about what’s been draining out of that sore on their, uh, leg, ask them to put it on speakerphone so you can ignore them.