As far as I can tell, the only defining characteristic of a private pilot is to be reasonably well off, which generally implies a pre-existing and reasonably high level of intelligence and discipline in our professional lives.
Well... You'd think, but not always... Some two decades or so, when I was still a newer pilot, having about 1500 hours, the boss began to send me flying with clients in their rather "well off" planes. Certainly the clients were well off, but in terms of aviation (in some cases), it was well off with money, not so much experience. I began to realize that the well off client, who was flying his pride and joy 185 amphibian, really had little idea of how close he was coming to getting into difficulty sometimes. Assume nothing about piloting skill, based on life success!
A professional and successful business person, who reaches the point in life where they can afford to fly, cannot be assumed to have the flying experience to back it up. I present JFK Junior as an example of this....
Yeah, I've made lots of mistakes - as recently as today! In truth, many should have been fatal, but with little more than luck, the "swiss cheese holes" did not line up, and I did not fall through. I opine that the real skill in a person, is to not only recognize the mistake, but correctly place it in the context of why did it happen (so as to prevent a repeat) and what were the consequences. How would you do it differently next time, or more simply, what did you learn,
and how will you apply it!
Bad enough something bad happened, or nearly so, but worse, you don't learn from it, and it happens again and again.
My job is to test and assess that a modified aircraft is compliant and safe. So I'm constantly trying to figure out how to design out opportunities for pilots to make mistakes. Still though, after having approved several hundred modifications, four pilots have still found a way to kill themselves in a modified aircraft I had flight tested, and approved. The design standards, and format for flight manuals and placards is intended to design out mistakes -
if the pilot follows them!
But there's a more basic layer than that. Pilots, no matter how successful, must always remind themselves, that they are still a soft bit of skin hurtling through the sky, and if they are not skilled and cautious, the plane is going to kill them. The sly and the ground, don't know they are "successful"! Pilots must only venture far away from their skill set, under competent supervision.