It’s easy to be surprised with both your eyes sewn closed.
I’d say the major cause of surprise in the world is unconscious self-deception — also known as hope.
How profound those Greeks were who smiled to think that, while all others evil had been unleashed in the world, at least hope had stayed in Pandora’s Box. And how much more profound that their word for honest, “alethos”, really should have meant “those who do not forget”.
And perhaps they were so profound precisely because their beliefs were believed with full sincerity, even if those beliefs were only half-truths.
I think we moderns too often lack the courage to be passionately and willfully wrong: we are almost exclusively wrong out of confusion and cowardice.