Why did Adam ate the apple? Is the curiosity of the forbidden fruit that drives people touching freshly painted walls. It's the answer of the eternal question of "what will it happen if..." that sometimes even urges people to do that. I know that it might sound weird, but I guess people want to learn from their own experience how things work, why is that bad or not and how this will affect them. Not all of them, of course, but most have this "in their blood". They simply can't hold themselves away. I'm that type of person sometimes also and I have that since childhood. I tested an old oven with my hand and I got burned. Too curious sometimes...