The active imagination has no trouble imagining the negative outcomes of your new plan, your next speech or that meeting you have coming up.
It's easy to visualize and even rehearse all the things that can go wrong.
The thing is: clear visualization, repeated again and again, doesn't actually decrease the chances you're going to fail. In fact, it probably increases the odds.
When you choose to visualize the path that works, you're more likely to shore it up and create an environment where it can take place.
Rehearsing failure is simply a bad habit, not a productive use of your time.