why do songs evoke such emotion?

I was listening to mad world by Gary Jules and somewhere it hit my emotional strings. last year I went into a depression and thought there was no hope for me when somebody showed me that there is more to life and I have a purpose to fulfill. listening to this song has value to me and I can relate to it the most since I tend to have a lack of emotion since it tends to play tricks on you, but that doesn't mean that I"m cold hearted I still care about other people and all I just cannot relate any emotion behind it.

Here's the song and the lyrics.