I have played several role playing systems. My favorite ones are AD&D, Champions, and G.U.R.P.S.. The characters I have played over the years have seen and done things that can best be described as invigorating. To be able to heroicly save the day and yet still feel some of the trepidation that your character can be gone with a roll of the dice and the uncaring decision of a friend who holds the power to create a universe that bends to his/her whim.
OK, Thats the melodrama of it. Still the fun of marching toward that possibly deadly trap or turning the corner to be confronted with overwhelming odds, then turning that situation into a victory and a reason to gloat about your ability to react and solve the problem. It can be intoxicating. I know that without direction and understanding anything that intoxicating can lead to distruction. I feel that such games should have an "Mature Adult" leading and guiding the participents. Too often there is no one to help make the decisions or suggestions that can prevent the destructive side. People are quick to condemn the games without looking at the potential gifts that the game can impart to young minds. Problem solving abilities, coping with tradgedy, understanding politics(if anyone truly can!) and using the game genre's to enrich a child with knowledge of history, mythology and how to build a campfire.
I will add sections on diffent campaignes I have been a part of to basically boast and revel in my past accomplishments.