Music means something different to everyone who hears it. While the appreciation of all forms of art depends on taste, the listener's response to music is different than a viewer's response to a movie or a reader's response to a novel.
Most forms of media that we consume on a daily basis are formed around a story. When we like an article or book, we like the plot and the setting and the characters. The same goes for movie or television show, perhaps including our love for a specific actress or actor or even filming style. Our response to these outlets has to do with how well we relate to and connect with the characters created by the author or writer. Our appreciation stems from a human connection, the ability to take an unreliable world and bring it into our real lives.
With music, it is quite the opposite. While our affinity for the tune, beat and vocals play a role in how much we like a song, we often respond to music based on how it fits into our lives. We build an emotional connection to songs based on when and where we heard them. Instead of connecting to the characters or plot line of a book or movie, we connect the emotions of a song to the characters and plot line of our own lives.
Other art forms help to remove us from the ordinary. They create totally new universes that take us away from the mundane of our everyday lives. They are constructed in a way that most people will react to in the same way. For example, we all cry at the sad parts and laugh at the funny parts and love the good guys and hate the bad guys. But for music it is different. For some people a song can represent happiness because they heard it on a day when they got good news, for others, it can represent stress because they heard it on a day that they felt overwhelmed. The difference is that music is left open to the listener's interpretation.
The fluidity of music allows us to transform its meaning as we hear it, rather than transform our feelings as it plays for us. Rather than telling us how to feel, it gives us a melody and some lyrics, to set our feelings and lives to.