And on the contrary, one who is sad because of the bad thoughts, shows that he does not know the level he is on and he thinks that he can be a tsaddik, and therefore he is sad that he is not a tsaddik. But if he would have known that he is far away from being a tsaddik, and maybe not even a benoni, he would not be sad. Since this is what the benoni needs to do, to push away the bad thought.