[yariang]

I agree. I've also found people with hobbies that are dangerous tend to be more mature. For example, people that go hiking, rock climbing, etc... I am not sure why and I am wary of saying it is because stupidity will get you killed in those situations and a more serious outlook serves you well, but that is one possible reason.

[gorydetails]

It takes serious planning and visualization over several years to excel at a demanding hobby. It requires dedication for the sake of its intrinsic rewards. These sorts of hobbies rarely have the potential to "turn into a business." Any serious practitioner has effectively self-selected as a person who has the means, makes the time, and has a passion for the pursuit of personal fulfillment.

[yariang]

+1 for wording it so well. I might add that it also takes a person who is willing to accept full responsibility for his actions and the actions of others in his group since nature takes no excuses.