Sensible optimism is a belief that the odds are in your favor, and over time things will balance out to a good outcome even if what happens in between is filled with misery. And in fact you know it will be filled with misery. You can be optimistic that the long-term growth trajectory is up and to the right, but equally sure that the road between now and then is filled with landmines, and always will be. Those two things are not mutually exclusive.