Another aspect of self-discipline is the habit of thinking and forgetting: to be able to think of the same thing of which one wishes to think, to continue to think of it, to hold that thought - and to practice to forget things, that the thoughts may not get a hold over one's mind. By doing so one becomes the master of one's mind, in the same way trying to check thoughts of agitation, anger, depression, prejudice, hatred. This gives moral discipline.