Sometimes we are depressed. Sometimes happy. Sometimes depression is so serious that some of us need medical help. Some of us commit suicide . How to decide whether we should be happy or sad ?  What is the yardstick ?  Each of us think that our grief is unique, so how to decide ?
Consider this seriously.  “If you woke up 20 years ago and realized all that you have experienced, lost or gained in these 20 years , was a dream  , then how will you react ?  Will that realization make you happy or sad ?  Consider this carefully, here is your answer.  You may change the 20 yr period according to your preferences.