Are difficult experiences valuable lessons for the future?

During our life-long time, there are times of frustration as well as times of happiness. Life is realistic and sometimes cruel, no body can lead a smooth and happy life without encountering any difficulties and obstacles. So the question is how to look at these setbacks and bad lucks. In my opinion, if you always uphold such a view that, most experiences in our lives that seemed difficult at the time will become valuable lessons for the future, then you will no only successful overcome your current difficulties but also enable you to hold a healthy attitude toward life. As a matter of fact, these frustration and unhappy experience exert an import and far-reaching influence upon our later life. 

As the foremost reason, the past setbacks and frustration will teach you how to cherish your current peaceful life. Undoubtedly, life is a combination of painful struggle and happy harvest. There is an old saying in China which goes like this: no pain, no gain. So it is only after experienced all these hardness, you can realize that the peaceful daily life is a kind of happiness and then you will cherish it more than before. Actually, the one, who never taste the bitter of pain, can never truly understand what the life is, how to enjoy life, as well as how to lead a meaningful life.  

Another strong argument for my avocation is that the past painful setbacks will remind you, from time to time, to avoid the similar mistake you offended past when you encounter the same situation again. And it will also offer you a rich experience to overcome this kind of difficulties. Moreover, this time, when you bad luck come again, you have become more mature, composure and experienced for your past frustrations have offered you strong reference background.  

There may be other reasons available to defense my argument, but as far as I am concerned, above two are the most convincing ones. Personally, I truly regard the past difficulties and frustration as the most valuable lesson to our later life.