Couldn't agree more. Every change that happens in our lives is the result of the thoughts we feed in our mind. Just like our body which is the result of the food we feed it.
Thoughts are things.
Being positive is a choice. A choice that is difficult to act upon. And the main reason for people producing negative thoughts is the environment they live in and the people they interact with. It takes a lot to train the mind to produce the right thoughts all the time. For some, it's easy to do, but for some, it can be a pain as people can have different reasons because of which the negative thoughts get produced. Since childhood, that mental conditioning of our thoughts have happened and that's the reason it's so difficult to keep oneself positive all the time.
I personally have felt it very difficult at times and it does take some serious efforts to do that. But once you have trained your mind enough to produce positive thoughts, nothing can touch your soul but that needs the enlightenment of the soul.
Upvoted! :)