I think the discussion of tattoos should be banned to those who are middle-aged or older, and extremely nerdy. Because we all know they hate tattoos, and have no real grasp on what is "in" and what isn't.
And the argument of "do they realize they will have this tattoo when they are old?" is seriously weak. Believe it or not, not everyone lives their life planning up to when they are old and decrepit. Some people like to live in the now. I for example, ride motorcycles, base jump, and skydive. I could honestly care less how anything I do today, is going to affect me when I am 70. I would actually prefer not to reach that age.
I am pretty sure your comments reflect IQ more than age.

That's one way to admit you are old
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Empirical studies seem to show that 'living in the now' corresponds to higher levels of happiness, but I haven't seen longitudinal studies on this, particularly dealing with risk junkies.
I can show you the results. Come with me to one of the many bars in small towns across the country. You will see countless unhappy middle-aged men who spent their life making the safe choices.
Come with me to a cemetary or an intense care unit and I'll show you old and young men who made very stupid short sighted choices when they were young.
Well then I am willing to bet that they don't regret their choices
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Actually, I have to agree with that.
I would visit the paralyzed individuals.
These last few comments though are off base. People are different. Extreme sports are appropriate for some people and not for others. There is no need to force everyone to be the same. Someone who gets panic attacks from heights isn't going to enjoy diving off of a cliff.
I don't want to get into the whole issue of hedonic adaptation, but there is an application here once we become accustom to certain levels of stimulus.
In the end, whatever floats your boat. Each of us will face the consequences of our own actions and inactions, so it isn't really anyone else's place to judge if no one else is being harmed by our actions. Some people get a thrill from skydiving. Some people get a thrill from reading about String Theory.
The kids argument is out of place because it is irrelevant if someone doesn't have kids yet. At that point, overly risky behavior becomes irresponsible (though I question how risky sky diving actually is if you know what you are doing).