Does an increase in confidence inherently result in a decrease in common sense?

I guess I still have the idea of confidence on the brain as I have been considering my confidence issues with those of today's youth. I'm not saying I was a perfect angel as a child or that I didn't know anyone who lived their lives with complete reckless abandon and a disregard for rules and regulations but I have noticed a severe increase in kids filled with apathy when it comes to socially acceptable behaviour.

Am I painting myself as an old fuddy-duddy now? I don't care.

When I was young (and even now) I considered myself a smart-ass. A fact I was and am proud of. Although I don't consider myself quite as hilarious as I did when I was twelve, when everything I said was pure gold comedy, I do still pride myself in having a sharp tongue and a biting wit. However as much as I know it now, I hold that even in my younger days there was a time and a place for sarcastic responses and I knew where to draw the line. Sarcasm and mockery was reserved for amongst my friends or to be said quietly in the back of a classroom to the chortles of my cohorts. It was not blurted out for all to hear, which would result in unwanted attention. This reserve, this joy of being secretly funny behind the backs of authority seems to have vanished amid the posturing and cockiness of a new generation.

I laud this generation's confidence, their sheer self belief in their own abilities and right to accomplish whatever they set their mind to. I can see major benefits for a generation that does not contain a lot of the fear, shame and lack of confidence that I portrayed as a youth.
Yet I have noticed a lot of downsides to this confidence. Their lack of shame in a given situation although beneficial at times in allowing them to achieve goals also seems to lead to a lack of concern or regret for when they actually do things wrong.

This is a generation that wins arguments by being loud rather than by showing reason and if you don't like it well what do they care; you're just stupid! Their confidence seems to have arrived with an undeserved sense of entitlement and a certain amount of delusion with regard to their own abilities, as can be seen in the plethora of reality shows where people expect fame without any talent to back it up.

Common sense seems to have taken serious losses for the sake of confidence and instead of knowing where to draw the line or when enough is enough, I find a large proportion of kids would rather dig in and draw more attention to themselves and even get themselves in serious trouble rather than let common sense and cooler heads prevail.
I'm all for confidence and self belief but does it really have to come at the price of common sense?