Psychiatrists declare that most of our fatigue derives from our mental and emotional attitudes... What kinds of emotional factors tire the sedentary (or sitting) worker? Joy? Contentment? No! Never! Boredom, resentment, a feeling of not being appreciated, a feeling of futility, hurry, anxiety, worry-those are the emotional factors that exhaust the sitting worker, make him susceptible to colds, reduce his output, and send him home with a nervous headache. Yes, we get tired because our emotions produce nervous tensions in the body.
Dale CarnegieThe most important thing in life is not simply to capitalize on your gains. Any fool can do that. The important thing is to profit from your losses. That requires intelligence, and makes the difference between a man of sense and a fool.
Dale CarnegieEnthusiasm is that ingredient of vitality mixed with a firm belief in what you are doing that ensures the success of any project you undertake.
Dale Carnegie