Should WW2 have happend?

In World Wars we talked about if WW2 was even necessary. I personally feel it was going to happen no matter what. I feel there are two man reasons that the war started. 1. The Treaty of Versailles was very unfair towards the Germans ,and they just weren't going to stand for it anymore. 2. I think that once Hitler took over Czechoslovakia, that really made the British go to war and so they did.