Striking the balance between letting your kids get hurt and protecting them is one of the hardest things to get right, in my opinion.
I think my wife tends a little too much towards protection, and she thinks I tend a little too much towards letting them get hurt. So it probably works out about right.
Obviously I'd like to protect them from some of the worst things that I experienced (concussions, big sets of stitches, still no feeling in my eyebrow or chin, broken bones, etc) but some of those things are inevitable if you're doing fun stuff and pushing yourself.