Dickens' A Christmas Carol is a story of redemption. Remember that Scrooge had a lot of bad things happen when he was young, so we can understand how he became a miser who only cared about money. Scrooge didn't even care about his own comfort. He lived in old almost abandoned house, ate bad food, and did not live well, even though he was rich.
Money for him was about power and control. It meant he was safe. Safe from all the bad things that had happened when he was younger.
His old partner, who was just as bad as he, comes to visit him as a ghost because he says his hurt himself through greed when he was alive and even though he was a miser, he cares about his old friend and partner and wants to help him.
So when the ghosts come to talk to Scrooge, they're all coming to help him. For him this is a very strange thing. The only people he really cared about or trusted were his deceased sister and his fiancée, who he abandoned because money was more important to him than love.
Scrooge had a very modern Republican Party attitude toward poor people. If you are poor, it must be your fault. The ghosts show him that this isn't true and he begins to realize that the poor aren't things, they are people. Maybe the most important moment is when he remembers the party his old employer gave to his workers every Christmas. It didn't cost much but it made everybody so very happy. That's when Scrooge realizes that you can have money and be powerful and cut yourself off from everyone or you can use your money to make everyone, including yourself, happier.
The best real world example of a Scrooge is Howard Hughes. Fabulously wealthy, perhaps the wealthiest man in the world, he ended his life hiding in a hotel room in Las Vegas, shuffling around using empty Kleenex boxes for slippers, terrified people were out to get him. He was mentally ill, but human relationships could have helped him find stability.
In other words, whatever it is which makes people insane, you can help it destroy you by becoming greedy and cutting yourself off from the humanity of everyone else. We need to remember we are all one family. When you make someone else happy, it makes you happy. Recent experiments using functional magnetic resonance imaging show that the pleasure centers of the brain light up when we do kind things for other people. It's a real thing and cannot be ignored.
I also want to mention the moral belief system currently very popular among many elected officials. Ayn Rand says selfishness is everything. Greed is good. You should care about no one but yourself. Many people call her a philosopher, which is ridiculous. Philosophers think things through an attempt to understand life through the understanding which grows from the development of their ideas . All she ever did was scream and hiss about how evil collectivism was.
She never thought anything through, she just hysterically reacted. She also got everything wrong. Modern science has shown in many ways that man is a social animal and that we naturally work together. We are a species which practices reciprocity by nature. She is wrong sociologically. She is wrong psychologically. She is wrong in primatology, and so on. The reason people love her so much is that she gives excuses them to do doing horrible things and makes them feel good about it.