Difficult experiences become valuable lessons in future life. Agree or not?

Most experiences in our lives that seemed difficult at the time become valuable lessons for the future. Use reasons and specific examples to support your answer. Do you agree or disagree with the following statement?

Life is full vicissitudes, which we usually find quite challenging and complicated at many different levels. People often believe that these hardships of our lives usually leave valuable lessons for us in later life and I, too, opine that the most experiences that were difficult at the time become necessary lesson for the rest of life. 

First of all, I strongly feel that experience is the best teacher. While trying to deal with obstacles in life, people may discover many harsh facts of life and they will use that experience in the next similar problems in the future. For example, a person who loses his father because unexpectedly at young age,  may feel that his life is miserable. During the initial period he has to bite the bullet more than often in routine life, but gradually he will learn to overcome the obstacles of his life by himself and that experience would help him become a well-mature person at very young age; normally, when others of his age would be just spending time in playing and studying. Hence, the process and tenure during which one fights the odds in their life, serves to be unforgettable but priceless lessons for whole life.  

Secondly, people tend to remember things that put them in serious or difficult situations, thus those things will properly be in their minds for a long time and become worth-having lessons. In fact, there are a lot of things that happen every day in our lives. Hence, if an event is not special or we easily handle with it, nothing retained in our minds later. For example, one who easily puts trust in everybody, might learn a lesson to be cautious if he suffers from any cheating or fraud from somebody. In this case, if person always keeps trusting, and no boy breaks his trust, he might not be having any specific memory or significant lessons for future life. 

Furthermore, only difficult experiences help people to understand their surrounding better. Actually, we cannot know a person completely in normal circumstances because people‘s true characteristics are often hidden in the profound depth of their minds. As an instance, when we are in trouble, those who are ready to help or at least share our bad time with us are our indeed friends. In that case, we can realize that not everyone we know is our friend and we will know how to sort out those difficult situations like that.

To sum up, Although, difficult phases of life seem really unbearable at a time, I strongly believe that most of the valuable lessons in our lives come from such difficult experiences only.