“We don't rise to the level of our expectations, we fall to the level of our training.” Reading about it generates expectations, and they can be deadly.
On average we fall to the level of our training, but then there's moment to moment variation because of "human error" which has little to do with lack of skill or training, and more to do with individual and situational factors.
Training is critical, but even then you can still fail, which is why layers of backups are great.
For a lot of us, skill might never be as reliable as other layers, but it's generally different from other layers making it less likely to fail at the same time because of the same cause.
Crew Resource Management has a lot of great insights.