Our conversations and discussions often turn into a sparring match to see who can be the cleverest or the most insightful or knowledgeable, or who can dominate the discourse by getting the most words in edgewise. Communication gives way to competition. We just aren't conditioned to wait for someone else to finish his or her thought before we jump in with our response. Usually in our conversations, while one person is talking, the other person isn't listening, but already formulating a response. I think it's because we don't really place value on listening in our culture so much as we do on proving ourselves.
Some cultures have a far different approach.
In some cultures the expectation is not only that you allow someone to complete their thought, but that you also allow a moment of silence before you say anything in response, a moment to let what has been said resonate and sink in. But if we were to cultivate an ability to really listen, it would probably go a long way toward enhancing communication and reducing conflict. Here in the U.S. we talk sort of like we drive. It's the same in conversation. If we allow a moment of silence, someone will invariably jump in and cut us off.