OK, jokes aside, I'll try to explain it to you: music is a form of communication. This communication can come from the music itself, or from the lyrics, or from a combination of the two. This communication is usually emotive, exploring and conveying a feeling or a mood (a sad ballad will make you pensive, a jolly, lilting tune will make you smile, etc), but it doesn't need to be exclusively emotive:
the sounds themselves (quite apart from their emotional impact) can be a source of pleasure or interest (or both) on their own. The way a melody moves up and down a scale, or crosses to a different scale, and the vertical structure of a musical piece (ie. harmonies or dissonances) can stimulate and excite our brains. The music of Bach exemplifies this, as it's frequently devoid of emotionalism (even though some modern performers like to exaggerate elements of it to make it sound more emotional, but you can get historically-accurate period performances to hear what it's meant to be like) but still "moves" us. Many Mozart pieces are also this way: like listening to a very charming, eloquent fellow holding forth on a subject dear to his interests. If you try to "visualise the music" (in a non-synaesthetic way
), you can sort of imagine each melodic theme being a different argument, a change in orchestration being a rhetorical device, a trill or turn being a jocular aside intended to arouse the laughter of his listeners, and a harmonic shift being an adjustment the emotional appeal of his argument. WHAT this hypothetical speaker is saying I don't know, because the argument is musical, not verbal, or philosophical, or emotional, and doesn't always translate to real-world stuff. It CAN, if you put it in the right context, or if the composer writes it deliberately to convey particular things, or if the accompanying lyrics are doing so, but it can also be its own language, and "say" things which can't be verbalised in any human language.
It's like the old adage "jazz is like a good conversation". Which this guy took kinda literally
(clicky) but tbh he verbalises what music does to people better than I explain it here, and if you can "get" why that video is funny then you've come as close to understanding what I'm trying to say above as is possible without feeling it yourself.
Why our brains are excited by music I don't know, it's hard-wired into us. This has been confirmed by scans of people's brain activitiy, even as infants. If you've never felt it, then either there's something wrong with you, or (the more likely explanation), you've been listening to crap music all your life.
. To me, music is like oxygen, I just couldn't live without it. 
If you liked that vid check out his others, the guy used to be a professional stand-up comedian who burnt out of show biz and is only just now making a comeback via Youtube - that used to be part of his routine! 
