Ever had regrets? Wish you could change something?
Look at all these zombies from Night of the Living Dead!
Why did they come back and why are they so sad and angry?
It's simple, but the cameras never showed this part - they came back to get some life insurance but their agent said, "No - you're dead! It's too late!"
So now they roam around knowing that they did not leave behind what their families needed - and it makes them sad, and angry...especially when they see someone who can still get life insurance! That's why they attack!
Get some life insurance - your family needs it and you won't have to get all sad and angry when you die. Your family may still have to deal with zombies but at least they will have money for guns and ammo!