The vibration and frequency of sound has a lot to do with our responses. For me, low frequency sounds are much more appealing than high pitched frequencies. A french horn sounds a lot more pleasing than an ambulance siren. I'm pretty sure I wouldn't get out of the way as quickly for an emergency french horn. It just doesn't say, "red alert" like a shrill siren does.
Anyway, the above video describes the science of sound in a simple and much better way than I have. Go science!