Tapas: The fire in your practice.

Tapas (Austerity) is one of the most powerful concepts in the Yoga Sutra. A better way to understand tapas is to think of it as consistency in striving toward your goals: getting on the yoga mat every day, sitting on the meditation cushion every day—or forgiving your mate or your child for the 10,000th time. If you think of tapas in this vein, it becomes a more subtle but more constant practice, a practice concerned with the quality of life and relationships rather than focused on whether you can grit your teeth through another few seconds in a difficult asana. - Yogajournal