Managing your emotions can be the key to how you experience reality. Think about when you feel angry compared to feeling happy or sad. The world looks different depending on which emotion is currently working to hijack or liberate your perceptions of reality.
This is not about believing that this is happening, you are just giving your subconscious mind specific instructions. Practising changing your thoughts and feelings daily will help you master your emotions more effectively. And who knows you may just brighten up someone else’s day.