Should a movie convey a message to the public?

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We watch movies often in our life and most of us do it only as a part of entertainment. We doesn't except it to deliver us a message. But thinking deeply, movie is a media which can make a great impact of anything among the people. Of course, there are also movies conveying messages and morals to the people. But can't it be used to the maximum extent to do that? I'm interested in film technology. I need your opinions..plz