Thoughts on parenting

Wesley is in Nashville, and we are at home. Well, we're really at my in-laws' house. I am having issues latley with disciplining Knox. At the risk of shocking the world through a discussion on disciplining a 13 month old, here goes.
I guess I should start this conversation with the preface that we believe that a child-centered family is not beneficial to neither the parents, nor the children, nor the rest of the world, for that matter.
We began this process of trying to let Knox understand that he integrates into our family, and is not the center or purpose of it, quite early in his life by letting him cry himself to sleep. You may not initially think that coorilates to teaching him that he is not the center of the family, but let me assure you, it does. I know this from experience. I would have thought a year ago that this perspective is nuts and couldn't possibly make sense, but I know from experience it is true. Knox is a very strong-willed child. He demands his way. But when I give him no other option at nap time (or at bedtime) but to sleep, he cannot have his way. His body gives in to sleep eventually, and any crying (aka rebellion, in many cases) just helps my case by tiring him out more. When he got old enough, we started to teach him "no" by thumping him firmly, but not too hard, on the hand or foot. He did not imidiately respond to this, because, as I said before, he is a very strong-willed child. He would sometimes look at me like, "what do you think you are doing?" and continue to reach for whatever he shouldn't. But he quickly learned what "no" means. He now has an understanding of consequenses for his actions. By the way, let me also add that he responds sometimes well to praise, so I do not want to give the illusion that we only punish him. No, we understand that at least equally, he needs praise for him to understand to do certain things. We cheer his obedience and creativity on with gusto.
Well, lately (within the past month, noticably) a new streak of rebellion has popped up. He tries new tactics. Where formerly he would mainly cry to get his way, now he whines and yells. He actually told me "no-no" after I told him no. I have seen him laying down on the floor and crying in anger (throwing a miniature temper tantrum) after he doesn't want to do what I tell him to do. Knox is about 13-14 months. He is starting to have more responsibility, and with that, is also learning that he can be more rebellious. His little rebellions are even so funny and almost sweet sometimes in that I can see what a frail and tiny man he is, and it makes me almost laugh with joy about who he is becoming, but I know I cannot laugh when he is being disciplined so that not to cause confusion.
It amazes me the capacity to learn that he has at such a young age. I would never have guessed that he could actually put his toys away on command this young. I didn't know he could understand how to sit down, stand up, or lay down when I tell him to do so. But he does. Anyway, parenting is so much more than I ever thought! :)