Here's why:
* Dissonance creates a feeling of tension or unease, urging the listener to resolve it. This is often achieved through the use of intervals that are considered "unpleasant" or "clashing" (like minor seconds, major sevenths, or tritones).
* Consonance, on the other hand, is a combination of tones that sounds stable and pleasing. This is typically achieved through intervals that are considered "smooth" or "harmonious" (like perfect fifths, major thirds, or perfect unisons).
In music, dissonances are often used to create dramatic effects, build tension, or lead to resolutions. They are a vital part of music's expressive power and contribute to the overall emotional impact of a piece.