I think it is the rebellion against normality, morality, ethics or whatever it is that they see as repression. They see what the requirement is and want to be the rebellious one, each one trying to be more radical than the previous. I work with juveniles and not only is the method of dressing and opinion on what constitutes appropriate vastly different then how I was raised, but their vocabulary is nothing but a series of reductions of common tongue. In 50 years we wont even be talking anymore it will just be a pronouncement of any particular vowel accompanied with a groan or bark.
**And let us not forget that schools teach them that they are a victim.
My children each have an I pad and I have installed a program which only allows a prescribed amount of time that they can use it before it goes into a time out mode, this coupled with a restriction on downloads that requires a password keeps me in control of what they view. I am very fortunate that my daughter would rather be outside than watching the I pad, she reserves that more for traveling and I allow one show before bed.
My wife was using the "don't make me get your father," until she recognized that it only reduces the respect shown to her. They know my follow through is swift but that the wife is a pushover. Now she is implementing more punishments as opposed to waiting for me. We have started a new thing for minor infractions in which we give my daughter a kitchen timer. The timer has a pre set mark that I put on it, she has to set the timer to that mark and carry it with her to the time out chair. She is not allowed to talk or get up until the timer goes off. We have situated the timeout chair in such a manner that it is away from all means of entertainment and that she must just sit there. I was not for it at first as I came from the school of spanking's (Many,many,many spankings..) but I have to say it is a marked improvement with out spanking her. For the big things spankings are still the order of the day but for minor compliance issues I like this method.