I'm thinking about this long and hard most of the days of my life. What is depression? What is causing all the problems in our minds and souls? If you think about it, it might come easy. Every problem with depression—almost ever—has been the result of human causes. It's not that natural to feel depressed.
... Given the circumstances in which this problem develops, it should take an animal months or years to become depressed. It is very likely that if an animal is devastated enough to feel depressed, they are in fact in a situation where their life is at danger so either it will not last or their life will not last enough for the development to complete.
There is something huge and important about knowing words. When I was a child, I used to wish to be cool.
For years my mind wondered about all the attributes that makes something cool and I wanted to have them all. I wanted to be "Cool". Years later, I was watching a YouTube about charisma. It was talking about the character "Cool", and why being cool is a way of charisma. It was in a way to dismiss others, hold a certain attitude, things we're all familiar with. And it was about the character of Iron Man, why is he cool. I never wanted to be that. It was way out of what I wanted to be. There I just realized that being cool, is to be "cold". I had never thought about the word associated with the concept. If I had noticed the definition, maybe I never wanted to be cool. I wanted to be "warm" instead.
After that revelation, I started noticing more and more that most of the times, words carry really huge meanings. It was as if there exists a forgotten world hidden behind these tiny words we say─and never think about─every day.
That said, there are also other things worth thinking about.