This really is an interesting question and has made me think deeply. I DO cry at some songs. There are songs I can't sing because my voice breaks up when I try, and yet there are those which make me want to puke, and, offhand, I can't work out what the difference is. Sentimental songs in the "Country and Western" genre I often find mawkish and sickly, but not always. Someone mentioned Eric Bogle as a sickening song writer. I went to a concert of his and was completely breath taken by the power of the emotion in some of his songs. Some of it, I'm sure, has to do with the sincerity of the feeling of the person who writes the song in the first place, but again, not always. I don't know what the answer is, but I do know that I will be listening with a different ear in the future.