Why do you need wars?

Answer 1

You don't need wars. Some reasons a group might go to war is:

-To defend the country from an attacker

-To defend Another Country from an attacker

-To build an empire through conquest

-To gain wealth and/or power

-To liberate another country

-To prevent a future attack

-To prevent another nation from gaining too much power

Answer 2

Territory conflict, idealogical conflict, broken treaties, wealth acquisition, glory, simple bloodlust, and occasionally revolution if human beings believe they are mistreated.