P.M.
Kids get mad, just like adults. And their coping skills and impulse control are teensy compared to ours. Add limited choice and vocabulary to express their feelings, and it can become overwhelming. Time-outs, spanking, scolding and other punishment simply make everything more overwhelming for some children – resulting in a "reverse" effect for strong-willed kids.
What does tend to work for all kinds of kids is more empathy from the parent. Let the child know you see/understand how frustrated or angry he is, that it is hard not to get what he wants, that he is upset when his brother gets into his things, that he has to stop playing and come to the table – whatever the issue is.
The parents I've know who use the Emotion Coaching techniques in books like How to Talk So Kids Will Listen, and Listen So Kids Will Talk get surprisingly good results, with children of all personality types. If it's not already in your parenting library, I recommend it enthusiastically. This is NOT pushover parenting – you get to determine your reasonable limits and expectations. But it will teach you how to do this in a way that is more respectful of the child's needs, and therefore usually more effective.