The reason they quit is drama. Some people thrive on drama, even though it destroys them. Look at her explanation of losing weight. She can't just eat less and excercise more, she has to buy 12 DVDs and books and diets. When your life is like a roller coaster, you're on a ride rather than in control. Don't be fooled into thinking the high highs, the periods of uncontrollable joy are good, because those are just the rides up to the crest where the fall begins.