Sadness is a negative trait because at the root of sadness is selfishness. Feelings of sadness come from thinking too much about oneself. A sad person thinks: "I should have more than I do. I am missing a lot."

A person who thinks this way should realize that there is no reason why things should be any different than they are (although he would like them to be). That will make it much easier to accept reality.

If something can be changed, try to change it for the better. If it cannot be changed, demanding that things be different makes you needlessly unhappy.