1: They have been having a bad day and you get in their way, say something wrong, etc.
2: They are in a good/content mood and you do something to provoke/anger them
3: They have had anger bottled up for a while and can no longer stand it, thus lashing out at anybody.
and finally the fourth reason
4: Simply because they like to fight. That being said its generally not the best idea to pick a fight with a metal head because whether they look it or not they are most likely a good fighter. They have a tight-knit group of friends, whom they are loyal to and share a good connection with. They are educated and civil, contrary to popular belief.
Old-school punk kicks ass, but what’s all this emo/screamo/pop-punk shit. * Sigh * Kids these days.
retard trying to capitalise on the image: fred, the 24-year-old wannabee metalhead who thinks korn are heavy, and believes that rap has a place in metal.
NOT metal bands: Korn, Slipknot, Mudvayne, Godsmack, Limp Bizkit, etc