I live around insane people there is no other way to call them. I have seen this pattern in their attitude over and over, that saying is exactly right.
Every day I see those people trying to do the same thing over and over and be miserable because they are expecting good things in life to happen and it does not. And as a consequence, those people are mean and can't stand it...
That is pure insanity and no I will not use a softer word because people are uncomfortable with it. You have to call a cat a cat.