In horse racing they put these slats on either side of the horse's head, blocking the creatures peripheral vision. They're called blinders. They don't actually blind the horse, but they allow the horse to see only what's right in front of it; otherwise it might freak out and lose the race.
People live with blinders too; but ours are invisible, and much more sophisticated. Most of the time we don't even know they're there. Maybe we need them, though, because if we took everything all at once, we'd lose our minds. Or worse, our souls. We'd see, we'd hear, we'd feel so deeply that we might never resurface.
So we make decisions and base our lives on those decisions, never realizing we're only seeing one-tenth of the whole. Then we cling to our narrow conclusions like our lives depend on it.
Remember how they imprisoned Galileo for insisting the earth revolved around the sun? You can call those people ignorant, but it was more than mere ignorance. They had a lot to lose if they took off their blinders. Can you imagine how terrifying it must be suddenly realize that everything you believed about the nature of the universe is wrong? Most people don't realize how terrifying that is until it's their world being the one threatened...