For instance -- my 6 year old will sometimes go into a tailspin over his sister touching his things -- yell, scream, push, grab. I usually take him upstairs by the hand, sit him down in my lap, and get him to calm dow. then we go downstairs, he must apologize to his sister (which he does with real feeling), and put his toy away.
then it's over.
I don't think of this as particularly defiant, though it's difficult -- but since it seems out of his control, I don't especially worry about it after it's over... especially since he and his sister go back to playing, and he (my son) forgets about it as soon as the explosion is over.
How do other people think about this stuff?