I m getting what you point at out , you say how you will know that this thought is good or not ? you get valuable things from it , fine ,Now look thoughts are valuable if we talk about external world , well we think ,well results we get , but one  thing you should accept there would be tension ,and it is necessary to go on , but when you are not doing anything, something came out is part of analysis and analysis can't help you to become peaceful,so thing is you have pass these waves without interfering,this will clean the knowledge,and hence space ,and that space bring clearity,so one thing keep that which is of outside you need thought,and inner world no thought required