I agree on 'putting emotion into music causes it to become more than just a song', allthough to express emotion through music and actually succeed in doing so is a totally different matter.. not everyone is as gifted in expressing their emotions and reaching their fellow man as others are

imo there are two ways of creating art, one from the heart and one from the mind (knowledge, intellect), I believe that if you use your knowledge (e.g. of music theory) to enhance your music you'll succeed more in creating something that's not only genuine but also succeeds in delivering it

I believe music to have a certain logic which can only be seen by the heart, but sometimes we discover bits and pieces with our mind so we can create what we feel inside