I personally feel like there are different components of my brain and some of them just want to do something, and if I don't "distract" them then they do something arbitrary and maybe in turn distract me... but if I need them, and they are busy deciding some music I am listening to, I lose out on the maybe-even-often subconscious processing they do that gives me valuable insight. I thereby find some (mostly useless) tasks easier if I am seriously even playing a video game with a targeted skill while doing them (people hate me in meetings sometimes ;P), or maybe listening to music, but if I am doing the hard coding work I "should be doing" I just can't :(.