Mary and DAR have some good points. It is very, very easy to kill oneself in a small aircraft. There isn't much room for experimenting or error. I'm not very experienced and I've managed to scare myself a few times already..
I often compare with driving. How many of your friends and family are really, truly good drivers? I bet not many. Sure, they can drive from A to B. But do they slightly ease up on the brakes just before the full stop so to avoid that nodding brake jerk? Do they know where every car is in every lane around them, without having to nervously crane their neck and look? Do they parallel park with perfection every single time? Do they adapt and never drive too fast, nor too slow for the surface conditions? Are they pro's?
I bet very few.
I have so many friends that I've thought about encouraging into aviation, but after seeing them not even mastering the very basic skills of driving safely and well, I've changed my mind. It can't be learned - if you haven't figured out how to drive well after 20 years of doing nothing but, what hope is there for these people in an aeroplane flying 10hrs/year?
Many of the latest fatal crashes have been with super-experienced ex-airline or military pilots with 15.000hrs, so that just goes to show that experience in itself isn't the the solution. There's something else - an X-factor of some sort involved. It's not skills alone. If I'd have to venture, I'd say it's the ability to adapt one's risk-taking and capacity to the given circumstance and condition at hand.