This is a brilliant question, and the basis for a technique called Negative Visualization. It is interesting how thinking what could be worse can be beneficial to our lives.
Taking this a step further, we can think of absolutely the worst thing that could happen to us in the next few days, week, months, years, and then write it down, and then wait and see what actually happens.
You’ll find that the worst case scenario hardly ever plays out.
"I’ve had a lot of worries in my life, most of which never happened." Mark Twain