I think fear of pain is something that pushes people away from doing a lot of things. And if that fear was gone, because of the lack of ability to feel pain, people would start doing a lot more things.
If I couldn't feel pain, I wouldn't go apeshit with what I do in life. I'd probably try a lot of new things - some things that I would be normally afraid of trying - but I wouldn't be completely idiotic about it.
But I'd also probably become overly paranoid, because I'd want to check myself every ten seconds to make sure I didn't step on a piece of glass and make sure I'm not bleeding to death.
I'm only considering physical pain in this, by the way.
I'd hate not being able to feel mental/psychological pain, believe it or not. xD