I have to deal with  unexpected and sometimes seemingly irrational anger as well. In my  case, this has the potential to become extraordinarily problematic. To give you an idea, I'm 6'6 , I weigh about 270lbs and if you look at my picture, which is fairly recent, you can see that I'm not obese..I'm just a really big guy. So I have to really be careful to be even tempered, even if  I'm fuming inside, because I'll scare the hell out of most people if I lose it. Consequently, I need to diligently maintain control of my anger.

My advice for when you're feeling cranky is to exercise . Do something healthy to work off that extra venom. I take walks and sometime lift weights. Lately I've come to love isometrics, because they cost nothing and you can do them anywhere.

Another technique is the classic "write a letter filled with everything negative you want to say to someone or about something" . You just absolutely unload allof your baggge in the letter and rant to your hearts content, being as foul and angry as you want..and then you don't send it,  you destroy it. I do that  and  it really helps.