i was thinking of making a thread similar to this.

I don't know about you all but I live for music..
i couldnt handle life without it. ALL kinds of music sound great to me. you would be suprised what music i like.
infact, even if i don't like the sound, i appreciate it because music takes time to make and it's supposed to have a whole lot of meaning for those who made it.

i hate it when people talk bad about an entire genre of music because they heard a couple of songs.. it's so ignorant.

anyways
but to answer your question. like AR15 said, it's about pleasures. it's about senses. it's about certain tastes. it's about moods.
there's a lot of things that would affect our enjoyment of music.
but i think even the least musical person would appreciate the sound of a female(with talent) singing simple hums.
so basically, i think music is natural human behavior. to think of certain reasons why we like it is too difficult a question to answer.

like ghosty said, it's also about sound. people say the sound of a breeze is soothing.
i think sound, as a sense to us, is a big reason for our liking music.