Music Part 2

Hey guys!
So I'm still sick and in bed listening to music. :P So I was thinking about how I only used to listen to country music but now I love everything. Robert gave me a CD last year that had all Celtic music and some French rap. Actually a Flogging Molly song came on that got me thinking again... Anyways what classifies music? Do you have to understand it to like it? Does it have to have lyrics? Even nature sounds, storms, that one thing where people bang on trash cans? Seriously what do you believe classifies music?
Now for the second part of my post. Do you believe that certain people only listen to certain kinds of music? Or do you believe that you can tell what kind of music people listen to by looking at them? My best friend Michaela listens to Metal and by looking at her you would never guess that. (No offence Babe, I love you!) And with me I love so many different kinds of music, its impossible to peg me with just one type.
As always let me know what you believe/think!