If you do X, what is the worst thing that could happen? Now, what is the best thing that could happen? Are you prepared for both scenarios?
Perhaps you are weighing whether or not you should ask your boss for a raise.
What is the worst thing that could happen? This sounds negative, but it is very helpful. The worst possible thing probably will not happen, but answering this question gets your fear out in the open. If you are having a hard time making a decision or taking an action, this helps uncover what is holding you back.
So in our example, if you ask your boss for a raise what is the worst thing that could happen? They could say no and yell at you and throw you out of their office. They might tell you that you are not as good as you think you are and you are not worth a raise. In a very extreme situation they might even fire you. The worst thing that you uncover by answering this question is the thing that is holding you back from asking for that raise.
What is the best thing that could happen? Unless you suffer from fear of success, this is a fun question. Now you can think about the positive consequences of the decision or action that you are considering.
So, you ask your boss for a raise and the best thing that could happen is that you not only get the raise, but you get a raise and a promotion. Or you get twice the amount you requested.
Are you prepared for both scenarios? If you can handle whatever the worst thing is and whatever the best thing is, you are ready to make the decision or take the action.
In reality, when you ask your boss for a raise you probably will not face your worst case scenario and perhaps you will not face your best case scenario. But if you are prepared to handle either one, you have what you need to move forward.