How do i get my adrenaline up faster when i think im about to fight?

I seem picture myself as an aggresive person....But when im about to have a fight on the street or arguement i cant get my adrenaline pumping till about an hour later when its over....Then ill be mad.....My frendz are different..Someone will tell them to **** off or something and they will just walk up and throw punches....Im not really like that unless im drunk...For example yesterday i was standing by myself near some people sittin on a bench in the mall n i was sendin a text message on my fone and i had a feelin that one of the guys sittin down was starin at me so i looked at him and said "what" and he said **** off....i was thinkin to myself wtf is this guys problem..i just crossed the road and met up with my frendz 10 mins later ..but these guys were gone anyways....If somethin like that happened to one of my frends they wouldv had the adreneline to make a big scene in front of everyone and probably throw punches if they had to..How can i get my adrenaline up fast ?? thx