Gabriele Oettingen, a Professor of Psychology from New York University, thinks so. Oettingen spent 20 years researching and testing her theories on productivity, ultimately concluding that optimism and positive fantasies didn’t actually help people reach their goals but instead got in the way.
From my perspective, the issue isn't really about optimism vs. pessimism but rather it reveals the importance of risk identification and mitigation, even for personal goals. What will you do if certain things pop up to take you off course? If you are on a diet, what would you specifically order at various restaurants? How will you handle possible sabotage from a friend or family member? If you plan to complete a project by Tuesday, how will you deal with the possibility of a crisis emerging on Monday?
The point is, even if the situation doesn't happen, you will be better prepared if you've at least reflected on the possibilities and strategies that will be needed to navigate through the landmines.
Here's a quick summary video: