Your state is everything. If you can control my state, you control your creativity, your productivity and your ability to influence whoever you talk to. Your state as a teacher heavily influences the learning outcome of your class.
As an example, when I knew that I was in a bad mood one morning, I did something unusual. With 45 minutes to the start of my class, I changed and went downstairs and just ran and ran. Sweating it out calmed me down. By the end of the run I was sweating all over but in a much better state of mind. It was worth it. I was able to start the lesson genuinely feeling good.
You are always going to have weaknesses. Your life is always going to be imperfect. There will always be short term and long term problems you cannot solve. While you cannot always control these things, you can train yourself to focus on things that help your enter a more powerful state.
Focusing on your weakness (even when you are trying to change it) and your unhappiness and your problems cause you to be in a powerless state. No point staying there.
Focusing on your strength, what you already have and the brighter side of things, are not self-deluding. They help you to enter a more powerful state.
It does not mean that you avoid all your problems and weaknesses. When you enter a more powerful state, you am more equipped to tackle your problem. When you are stressed about a work issue, you don’t continue to stare at it. You break away, find something to perk yourself up, enter a more powerful state, then come back to face the problem. By then, you will find your problem much easier to solve.