It means you will have to listen to waste and dummy talk if so many flies are around. You will waste your time in meaningless discussions and speeches with no solid logic backing them up. Obviously, this khwab communicates a psychological issue and an issue of personality.
Being aware of the words you speak and the topic on which you are discussing with others is important. It is human nature to have a lot to say, but the most mature individual is the one who speaks less. In Islam, it is also said to speak only what is necessary. The sin of wasting your time is to waste another's, and the sin of wasting another's is even greater. This dream is a warning for you, so you should not follow it.If you see many flies in your dream then its mean that you always say which makes no results. You say mostly ordinary to others and they pay no attention on your sayings. You must improve your personality and should make your thinking right.