Do you control your thoughts or do your thoughts control you?

Throughout the duration of lockdown I have been reading and studying for my own personal development. What exactly is personal development? We studied it in school, but at such a young age I know I personally didn't value developing myself as I didn't understand quite what that meant. I think the things I have been learning and researching should be taught in schools as frankly there would a lot less hate and pain in the world for it. But, it must be taught by someone that is passionate about self-help and development and not simply the RE or English teacher that has some free classes in their diary. That being said, it is never too late to discover yourself and work on you. Before now, I have always thought that living my best life and working on myself equalled going to the gym 5 days a week, or doing my fake tan and nails to feel better about myself. Yes, these are coping mechanisms and they definitely boost serotonin levels in your brain, making you feel better as a