Why is there an expiration date on sour cream?

If most car accidents occur within five miles of home, why doesnt everyone just move 10 miles away?

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

I went to a bookstore and asked the saleswoman, Wheres the self-help section? She said if she told me, it would defeat the purpose.

If all those psychics know the winning lottery numbers, why are they all still working?