Write about a way in which music can affect a person's mood

If some one is happy but music reminds him of something sad he would be mad.

Music, like every other environmental factor, can change your emotions. Songs that represent or display certain emotions, like anger or sweetness, can change  your emotions. On the other hand, it can intensify a person's current emotion, (ex: someone turns on cheerful music to feel better but in the end only feels worse off). If we're talking about it scientifically, sound waves can calm or create a disturbance in our mind, causing mood switches.