On/off. Black/white. Up/down. Yes/no.
Most things can go either way. (Forget quantum physics, that's a whole 'nuther ball game.)
In business, people stress a lot about things that are out of their control. Will the presentation go well? Will I make the sale? Will the client sign the contract?
You can spend hours, days, months prepping to make everything perfect. But then something unexpected happens, or doesn't go the way you anticipated, and it throws you for a loop.
It's 50/50. You will get the result or you won't. There's talk of the mythical grey area or the wiggle room, but at the end of the day, you are going to walk away from the situation satisfied or disappointed.
If you can prepare for one of either eventualities, it makes it much easier to plan ahead and decide what your next move is.