Philosophical questions!

Why is there an expiration date on sour cream?

If man evolved from monkeys and apes, why do we still have monkeys and apes?

If there’s speed of light, so what's the speed of dark?

Why is it only drug dealers and software developers call their clients 'users'?

If you try to fail, and succeed, which have you done?

If the black box flight recorder is never damaged during a plane crash, why isn't the whole airplane made out of the stuff?