Really. There is a difference.
Hearing is simply perceiving sounds in your ear (if you are not hearing-impaired).
Listening, however, is something you consciously do. When listening, your brain should be processing what you hear. Also, you should be paying attention to and trying to understand what you hear when you are truly listening.
Unfortunately, some people only HEAR and do not LISTEN.
Have you ever experienced telling a story and the person you are talking to cuts you off and starts blabbering about something totally unrelated? Have you ever replied to a half-hearted How-Are-You-How-Was-Your-Weekend question while the person asking you that question simply walks away while you are replying? Have you ever asked a question and get a totally unrelated answer? Have you ever talked to someone who realized, in the middle of the conversation, that you were actually talking to them despite the fact that you called their attention right before you talked to them and they responded then?
I could go on, and on, and on...
Listening is not an easy task to some. It seems to require so much patience. We can sometimes blame it on the person's short attention-span.
Funny. Most of us probably have at least one friend or know someone who is "hard of listening". It's not too bad. You can start rambling about something so unrealistic to catch their attention. Sometimes it works, sometimes it doesn't. That's life.