It is a very complicated situation when trying to disciplin children. One does not want to stifle their growth or damage them early in life, but one cannot give them free reign since they are not mature to make informed descisions. In order to avoid the problems of discipline it may be important for the parents to set a finer example for their children during the early parts of their youth. Children are, when born, completely without characteristics and behaviours. Parents play very important parts in the development of behaviours. If the parents constantly fights or yell, it is more than likely that the child will develop a similarly belligerent personality.
It is important to ensure that when the child is born it is raised in an environment that results in the creation of positive behaviours, or those that would be least likely to result in a reason for disciplining the child. As the child matures, it will be giving greater personal freedom to go along with its greater ability to process information and make informed decisions.
While in theory this process should completely remove the need for discipline, practically it should at least result in a lessened need for it. Trying to punish a child for behaviours that were instilled in it at its infancy is not an adequate solution, care must be taken to prevent such things from occurring in the first place.
That being said, if this cannot be prevented, it is important to try and instill these positive behaviours as soon as possible and in a way that is not permanently harmful to the child physically or mentally and logical reasons should always be provided to the child. Saying simply, "I am the boss," is not conducive to change.

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The Capitalist maxim: The fortunate must not be restrained in the exercise of tyranny over the unfortunate. Bertrand Russell
Heroism on command, senseless violence, and all the loathsome nonsense that goes by the name of patriotism -how passionately I hate them! ~Albert Einstein