I’m not sure why I thought of this (maybe it’s because I’m running now) but I remember reading about professional athletes whose development is like a series of inclinations and plateaus alternating one after the other. Over a period a time they make dramatic gains in their performance until one day they reach a plateau where they level off for a while making minor improvements at best. Then after a while, again something happens to spark their development and they take off again in making dramatic improvements in their performance.
In thinking about this, I was reminded how similar it seemed to life itself. We may learn something, spending many months or years increasing our knowledge and skill level until one day we feel like we have mastered that knowledge. Sitting on that mountain top of knowledge, we may think we know it all and are masters over others below us. Thus we stop exploring, feeling as though we "know it all". That is until one day something happens. We see or experience something that let’s us look at life from a different angle or viewpoint, making us realize that our mastery is fleeting, as there are many more mysteries of life yet to be revealed.