I like to listen to Something really Fast and Pounding when I'm studying.
Nile, Anaal Nathrakh, Belphegor or Decrepit Birth, like a Wall of sound to completely block out everything else around me, So there's nothing else to do than Study.
Music that starts Crushing you, and doesn't stop until you're Grinded down to a powder.
I have lots of more artists like this to recommend, but that should give you a general outline of what I mean, and most people should already have those.
My mind is always focused and Calm anyway, and sharp like a Scalpel, I like classical as much as the Next guy, but I'd go completely mad if I were to calm down any more, I never really get pissed off, I just get Resentful and bitter,you could say.
I never snap or anything like that, I've been Desensitized beyond belief.
When I'm working, I like to listen to Techno, Trance, and All that, My work is so amazingly boring, I have to do anything to keep positive, I always slip into such Sheer boredom, like a really neutral state of mind, Sometimes I like to say disgusting things to people just to get a reaction.
I used to listen to Sleep Terror in the mornings before school, The sheer complexity just got me a kick start into being properly awake, Like you have to be so Alert to listen to it, So many notes just flying at you, it's awesome.
I constantly look for new music that makes me go "Holy shit", Like you get chills from the sheer epicness of it, Something as simple as that song "Those who cannot speak" by Shadows Fall used to do it for me, But now I listen to stuff like this, without any reaction <:'C
I think It's from learning a bit too much theory, Having heard songs that were too Brutal, Fast, Epic, Slow, Depressing, Catchy, or insane so I constantly have to Beat it Each time.
Pisses me off.
...And that's a little bit about me, Sorry for wall of crap.