No scenario in your head is real
The brain is a prediction machine. Its main purpose is to keep you alive and the better it can predict the future, the better it can keep you away from harm. So it will try to conceive all the possible scenarios it can, as to be able to avoid them. And, of course, it will focus on the bad scenarios, since that’s what it has to defend you from.
In theory, at least, because overthinking leads to nowhere good.
The way we think influences the way we feel and act. If we’re lingering on a bad outcome, we’ll begin to feel anxious, we might become fearful and we might act in such a way to avoid it altogether. ”Mission accomplished!”, says the brain.