yes indeed, children do grow so fast. I have a 6 and a half year old son, we usually spank him in the butt as punishment, or a week punishment of no tv and no games.
But we always talk to him, we explain why we got mad, not on him but on the things he did (his mistakes).
Also don't easily get mad and burst out shouting at him, this won't help, you'll just scare him.(been there, done that)
We always guarantee our unconditional love to him. We always let him feel that we always care though sometimes we are getting mad. Luckily, since he was a toddler, we didn't see him have tantrums over toys or goodies, never that he talked back... yes he also gets sad and mad for a while but then after minutes of talking and explanation he also felt better and learned a lesson.
We also remind him from time to time what not to do and what's to do, what's right and what's wrong...in this way he will remember his guidelines.

Anyways, to all the parents, goodluck to all of us rearing our children, may we always enjoy each and every moment of parenthood.