How to describe a person's character as extreme?

There are many kinds of inner extremes. I have seen these two kinds a lot: extreme pessimism and extreme optimism. How pessimistic is it? For example, after watching an episode of Animal World, I feel that human beings are so cruel. How can they eat animals? They are still alive. They think that all human beings in the world are dirty and cruel, including themselves, and then they don't eat meat for a while. To put it mildly, it is too simple and kind to know what natural selection means. To put it mildly, it is that the imagination is too rich and the thinking is flawed. Such extremely pessimistic people generally feel inferior and sensitive, and may have defects that they cannot change. When someone says it a few times, he will feel that he is not like others, and many things will be magnified.

Extreme optimism is like someone telling him that you are an adult now, and you will marry to support your family in a few years. You should have some ideas of your own, you can't listen to your parents and rely on them. He didn't think much afterwards, but told another person that I was only a few years old now and it would be several years before I could get married. How do I know what happened a few years later, right? Maybe I will be sensible in the future. Why think so much now? People don't say I cherish the present. I have to enjoy my present life, otherwise it will be too late to regret it later.

I really don't know what to say to this kind of person. I think I drank too much chicken soup for the soul. This kind of person is usually arrogant, self-motivated, overconfident in everything, and will talk about action but not. But his self-healing ability is particularly strong, and others say that he takes nothing seriously.