I think Whirlybird has made a very valid point - I think we do tend to be overcritical. In flying there is often seen as being only one correct way to do things; to talk on the radio, to join overhead, to lean engines etc. This is certainly picked up by student pilots, hence the angst when faced with flying with a strange instructor (we all know
that they will have their own 'correct' method of doing certain things).
And perhaps in Aviation there really are more absolutes than in other spheres of activity, so there is more opportunity to make mistakes because there are less grey areas.
And perhaps mixing with professional pilots and ATCers via PPruNe is not such a good idea either - the other people in the air and supporting us on the ground are such professionals that some people could feel very unworthy and therefore be very sensitive to criticisms as well.
I think it comes down to personality and maturity.
If you understand that you are not perfect, but if you accept this and manage your flying with this in mind, I think you will continue to learn from flying AND you will not mind flying with other pilots.
If on the other hand, you expect to be perfect and cannot function if you cannot maintain this fantasy in your mind, then flying will always be a nerve-wracking, and ultimately unfulfilling, activity.