How to Detach a Bad Thought From an External Object

Spinoza says that things that happen in your mind that you truly believe will manifest himself in your body. He believes that if we detach a bad thought from an external object with which we associate it and attack attach it instead to a new thought then the bad or the good feeling will go away If we had a good feeling. Spinoza also argues that there is no body modification that we can't develop a clear idea of because it has to have some kind of reason.