First of all, sound triggers an emotion. It tells us about the place, character, or time. We use short melodies to engage the audience. Sounds trick our brains, and they make us believe that we experience something in real life, even if it is not completely true. For instance, if you hear a human scream in a horror film, you experience that person’s feelings.
Moreover, they influence our mood. For example, when you choose heavy metal music for the alarm sound, you wake up nervous and anxious. However, while waking up with more calm music, we are at peace with ourselves.