Thousands of laws

If the human race is more civil than animals, than why do we need thousands of laws?

Jail for life

If putting someone in jail for life would solve the problem of repeat offenders, then how come nobody does it?

Age of consent

Why is the age of consent different in all states? Are people more mature in certain states than others?

Different speeding limits

Why are speeding limits different in all states? Are drivers better in certain states than others?