Danny Flynn is a 6 and a half year-old boy who lives with his parents, and younger sister. Mrs. Flynn began, "To look at my Danny, you would never know why we brought him to the mental health clinic. He looks like an angel… those greenish-blue eyes, and that curly blonde hair of his. But to live with him, he’s more like the devil reincarnated. Don’t get me wrong. I love my son but the problems we’re having with him are just not normal." The reason the Laughlin’s are seeking counseling is for John’s history of severe temper outbursts, both verbal and behavioral, and usually when "things don’t go his way" which is just about all the time. "And when he’s not having a tantrum, Danny is just plain old angry," adds Mr. Flynn. Danny’s most likely diagnosis is: