Experience

Sometimes the things which we learn from our own experience are the best , from that experience we can learn a lot of things . As you can see in above pic The Mother is teaching their kittens How hiss in more effective manner so that it push away the humans or some predators from which they had threat for their life , the mother can only teach to their kittens , but when the kittens are actually in some life threat situation and they can use it effectively than only we can say that they learn from their mother very well , otherwise the life is there to teach more and more similar lessons , it's up to us  whether we learn from it or just make same mistake again and again or we can learn from previous experience and face it in other way . So Experience plays the huge part in our life .