Sometimes, to alleviate someone's worry, people will say "What's the worst that can happen?"
I never say this. I don't even think it. Because I can, all too readily, think of the tenth worst thing that can happen or the eight or fifth, which are all so horrible who would want to go beyond that?
If you use this phrase, I can only think you have a poorly developed or sadly lacking imagination. But you probably sleep better than I do.