Time, generally is unchanging. Whether one wants it to go faster or slower, time moves at a constant speed. However, when one is having fun, time seems to go by faster and vice versa, when one is sad or bored, time goes by much, much slower. In this way, time is somewhat a reflection of ones emotions.
In a similar way, musical time is also reflective of ones emotions. Depending on the tempo at which a song is played, the mood of the song can change. For example, if one played a simple song like “Happy Birthday” at the normal speed, it sounds like a happy, joyous song. However, if one played the song at a very slow tempo, then the song will start to sound slow, sad and depressing. In the same way, if one played a serious song at a much faster tempo, then the song will start to sound festive or even silly. Musical time, unlike normal time, is changeable and by changing the time, or tempo, of musical pieces, a musician is able to convey the emotions desired, no matter what the song is.