I have found that music, writing, imagery any creative output highly enhances our current emotions, some better then others. Music is particularly good at doing this for some reason as it appears that its' sole original purpose was social in origin, it brought people together into groups for common experiences of effervecence, this is even one of the theories behind the origins of animism and early religeon, as these individuals experienced a unified single emotion bought about by the social influence of their music it could be raised to the level of hypnotical influence or control as powerful as the use of drugs (but mind altering materials may have also been used to reach a higher "level" within these tribes).
Today, music still has the same effect on our emotions, whether it has increased in power is up for debate. In reality rock and roll is probobly no more emotional than classical music, but the popular ethos of society probobly socially influences us to think of rock and roll with greater emotional variation so we may act out this influence.
Are these things bad? That's a good question, but we certainly use the same effect discussed by social scientists to stir effervensence in our churches today. This is good in that it brings Christians closer together under our common God by use of music... but it is bad in that sometime churches aim to create songs that inspire effervence more than they speak the truth. Sometimes I pull myself out of the group just to listen and watch and notice that I don't always agree in totality with what the songs sing, but they are sung anyways... when I think about them later they are meant to create a feeling or an emotion, sometimes its for something as sad as to make the song rhyme. Rhyming by the way is a memoric device to help you learn, and has the effect of being magical since ancient times (which is generally why it is used in songs, e.g. God of wonders beyond our GALAXY, you are HOLY... I thought that he was right here in spirit within the church, what is he doing in ANDROMEDA... GET BACK HERE GOD WE DON'T NEED YOU IN ANDROMEDA WE NEED YOU HERE!) Of course, what songs you agree with and which ones you disagree with is a matter of personal interpetation and personal beliefs. But remember them in context to what they can do, when used properly they can bond powerful friendships and enhance our life with God, but like any knowledge if used for ill, like indulging your anger to the point that you break your friendships in a fit of rage that doesn't even truly represent you.
In the end, strip it of it's scientific perspective... science tends to make everything sound... dead. Its good enough just to understand its power, not the reasons behind them, this especially true because we don't really know why music, a mathematical variation in air-based presure waves produces powerful reactions in our emotions, the same can be said of art... or a taco bell grilled stuffed burrito... hold that thought, gotto go!
Pascal