Why was nationalism an important factor in ww1?

People are prideful of their nation. Nationalism is a way of explaining or putting in words how much some people really love their country. Some people love their country so much... they made a war. it honestly like that...everyone spent Billions of dollars. just to prove they were better and lost.

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.