To be too positive is toxic. To have balanced thinking is more productive. We have to understand things change cycles in life. Nature changes. We change. People die. People live. Things fall away so you can have something different in its place. Life is a process and you are a process. You are a constant and life will move without you if you don't participate. When people insist on positivity in all situations, they could indeed hamper their own inner growth and problem-solving that requires them to look close at the negative roots. They may even find the lesson embedded inside in the problem and understand progress is true happiness.