Flutterby™! : The power of negative thinking

this Tweet from Rob Henderson recommending and quoting Thinking In Bets by Annie Duke:

Despite the popular wisdom that we achieve success through positive visualization, it turns out that incorporating negative visualization makes us more likely to achieve our goals. Gabriele Oettingen, professor of psychology at NYU and author of Rethinking Positive Thinking: Inside the New Science of Motiviation, has conducted over twenty years of research, consistently finding that people who imagine obstacles in the way of reaching their goals are more likely to achieve success, a process she has called "mental contrasting".

One of those studies is Cognitive Therapy and Research, Vol. 15, No. 2, 1991: Expectation, Fantasy and Weight Loss: Is the Impact of Positive Thinking Always Positive?, Gabriele Oettingen and Thomas A Wadden:

Both expectations and fantasies predicted weight loss, although in opposite directions. The more positive a subject's expectation of success, themore weight she lost. The more positive her fantaay about weight reduction, however, the smaller her weight loss.