Sloth is the great enemy -- the inspirer of cowardice, irresolution, self-pitying grief, and trivial, hairsplitting doubts. Sloth may also be a psychological cause of sickness. It is tempting to relax from our duties, take refuge in ill-health and hide under a nice warm blanket.
PatanjaliThe obstacles that distract thought are disease, apathy, doubt, carelessness, indolence, dissipation, false vision, failure to attain a firm basis in yoga, and restlessness.
PatanjaliIt is only when the correct practice is followed for a long time, without interruptions and with a quality of positive attitude and eagerness, that it can succeed.
Patanjali