Unless you have an aim, to make force by working against some mechanical or habitual side of yourself is not enough. One must work on oneself, deny oneself, so that the force goes into one's aim.

Now when you make a real effort or a relatively real effort, you never become negative when you fail. This is a sign. Your failure makes you think more and remember more. But when you make an effort in imagination, an imaginary effort, not a real effort, you become negative very quickly and pass into your gallery of self-pity with all its ancestral portraits.