I have experienced that many times, and I believe that it is for 2 reasons. First, I have read over the years that car acoustics are good in general, and second, I think car listening supresses the bass and treble, and brings the midrange very close so that you feel that you can hear things very clearly that you don't normally hear in the singers voice and other midrange details. It isn't as smooth, lifelike, textured or well balanced and dynamic as your home system, but yes, it can really communicate emotion at times!
