Uncertainty and Grace
If you think something bad is going to happen it puts you into a negative stance despite the uncertainty. This is a weak place to be. You are giving yourself over to what you think is inevitable when you cannot be certain it is.
Best to think and plan for the best possible outcome. Your stance is one of positivity, and that positivity rubs off onto other aspects of your life and becomes a positive motivator.
And when push comes to shove, this makes all the difference in the world.