OM,
I grew up with a dad like that, he'd be quite for months then BOOM!
Funny story: when I was 15 I was a "handful" (to say the least) and before banishing me to my maternal Grandfather'sk who was also a "handful" house to live for quite a while) we were sailing to Catalina on the family boat. I guess I was being a "handful" and at one point my Dad just walked up and tossed me overboard! Dad then proceeded to sail large circles around me while I treaded water, with my Mom saying I was going to drown and that a shark would eat me. He only let me aboard after I promised not to say a word for 12 hours.
I think that we're talking about a skill that needs to be learned, no one does to naturally as far as I can see. We decent folks, and I include myself only on the periphery of that group, always give the other person the benefit of the doubt. After a few decades I've discovered that letting it build up isn't a good idea. But we all know that. What I try to do is really be "in the moment" and think about what it is that someone is doing or saying at that moment. Then, say the best thing I can think of about that, and not the 38 other things that person has done that bug me.
The hardest person to do this with was my x-wife, whose responses to my comments were not proportional at all, at least in my opinion.
The other thing I've learned is that when I do blow up I need to apologize. That helps attenuate the negative effects, especially if the blow-up was public. Then the apology needs to be public the way I see it. Right after the apology I _then_ take the opportunity to list the 38 things explaining that the person has been driving me nuts and that was the reason I blew. (I suppose that's cheating on the apology

When you really figure this out, let us all know, as I don't know anyone who is really done learning "how".