The Terrible Twos

I have never believed that two is a particularly terrible age.  My two year-olds have always been fairly reasonable - they are toilet-trained, talking, walking, feeding themselves, fairly self-entertained, and reasonably tractable.  When they hit three, however, life is another matter.  Three year-olds are opinionated and give the appearance of being logical while not actually being so.  I'll take two over three any day.
Then William turned two.  He started out okay, but quickly went downhill.  He is pretty verbal, which means that he thinks that he can tell you what he wants.  But sometimes he doesn't know how to tell you want he wants and instead uses whatever words comes to mind.  Today he wanted something - I still have no idea what - and keep insisting that he wanted green.  And when I couldn't give him green and tried to patiently explain that I didn't understand him, he started screaming and crying.  Nothing would comfort him because he hadn't gotten green and our dinner conversations were drowned out by the wails of an angry toddler.  If unchecked, the screaming would have gone on indefinitely as William adamantly refuses to be soothed when he is angry.
This happens very often - if he gets the wrong spoon or the cookies are all gone or he has been given the wrong shirt or if he has to wear any clothes at all or if it is nap time or if it is time to get up from nap - and the house has been much louder lately.  It's very wearing. 
I have finally figured out how to short-circuit the screaming - it turns out that two year-olds can understand threats if they've been enacted enough times before - but that still doesn't stop the fits from happening in the first place. 
There usually isn't any warning, as William - when he's not been crossed - is actually a very happy, cheerful little boy.  He strides around the house in nothing but his underwear, happily chatting volubly to everyone about everything.  Usually he's compliant, folding his arms when asked or coming when he's been bidden.  He's a funny little parrot, repeating things he shouldn't have heard, which only makes us laugh and then he repeats them again.  My favorite thing is when I tell him 'you're welcome,' to his high, chirpy 'thank you!'  He invariably responds with 'thank you you're welcome!' and this will go on indefinitely until one of us (always me) gives up.
But then, without warning, he explodes in tears and screaming when something completely random goes wrong and his Mr. Hyde decides to show up.  I never know when this will happen as the same situation - being told that he must wait for his cookie - may produce a chirpy 'okay' or a full-blown tantrum.  It's Russian roulette, but with a loaded toddler instead of a gun.  I'm not sure which one is worse.
I think that if William was my first child, I would be tempted to go in for sterilization right now, but thankfully he is my sixth and I have been worn down by the toddlerhood of five other children and I know that this too shall pass.  One day (maybe when he is twenty) logic will completely kick in (okay, maybe forty?) and we can discuss things calmly and understand exactly what green is and why he wants it so badly.  The other children have all become increasingly reasonable to deal with and so I have no doubt that William will also follow normal human development and become more reasonable with time also.  I will continue to believe this because not holding out hope isn't a good idea.
Until then, however, I have some long, scream-filled days to deal with.  Wish me luck (and self-control for when it gets really, really bad).