I've once heard it said, that "it is only through sorrow that we learn, whereas it is in the ecstasy of happiness that we forget," (source missing/paraphrase). What are your thoughts and feelings on the matter?
I think that bad times and crises may help us to learn because they usually force us to question some of our ideas, habits and values on which we had not thought . But I'm not sure that sorrow itself is a good teacher.
Actually, it is not sorrow but failure that is the greatest teacher. In our hyper-sensitive society, people assign too high a value to sorrow and too little to joy (happiness is quite another matter, and I agree with Sophocles when he says, at the end of his Oedipus Rex, "Nobody can claim having been happy until reaching the last day of his life").
Failure, on the other hand, invites us to explore what is behind our actions, to revise our plans, to change our strategies. Sorrow —usually a melancholia without an evident origin since, as Freud reminds us, melancholia has to do with losing something that was never ours in the first place— is paralyzing, it leads you nowhere but into your own ego. Failure forces you to step outside of yourself and look at you as if you were somebody else, and then you can really analyze your situation. If we realize we are emotional because we have failed in something, it is time to forget tears and check our methods. Most people are not on a dead-end street. Usually, there is no real reason for sorrow, unless you are in a real situation of danger, or you have lost all you possessions, etc.
There is no denying the fact that sorrow brings about philosophical thoughts- some times to the extent of becoming morbid( interested in unpleasant things).
Two universally spoken proverbs are there to lend support to such feelings in human beings:
[a]We like tears more than cheers
[b]Our sweetest songs are those which have the saddest thoughts.