Over the past 5 years, I've been cultivating a YouTube playlist of videos that I think can create a growth mindset. A growth mindset is a belief that your most basic abilities can be developed through dedication and hard work. It leads to success and happiness.
Each of these videos puts forth the best arguments for why one should avoid being pessimistic, untruthful, or overly emotional. Each video is beginner-friendly and short (less than 30 minutes). I recommend watching them in order.
Here's a link to the YouTube playlist: https://youtube.com/playlist?list=PLi28YExsdpPL8cBbpHH5HQ5HXATlmQqAu
The key to success is to read great books. Develop your ability to read, speak persuasively, and write.
Nothing is worse than war. People in the past had it worse than you.