As a rule, we don't handle the unexpected well. When my grandfather died from lung cancer, it was a long, protracted ordeal involving hospice care. Everyone was prepared, nobody was surprised.
When my dad died from a massive heart attack in the middle of nowhere in Nevada, a month after retiring, it was a shock, nobody saw it coming. He didn't make it long enough for the life flight helicopter to get there. Reportedly his last words were "Oh no."
It's one thing to plan for a death, it's another to be slapped in the head with one.