I believe that everything happens for a reason. I learned this from our past events that shaped our world and everything that is happening today as it happens.
Things that happen may be good or bad for us at that moment and may help or harm us in the future. WW2 would be a good example of this because it was harmful to us back when it happened because a lot of Americans, Germans, Japanese and other nationalities died because of this war over WW1 and religion/beliefs. Millions of people never returned from the war alive. This was a bad thing that affected the people back then and it still affects us now. The good thing was that Germany was defeated and the world was safe from the terror that was their. Now if the Nazis were able to beat the Allie forces imagine what kind of world we would live in now. Most of the people you know that are of different nationalities and skin color or beliefs would not be alive at this moment and we would probably be speaking a different language as well.
Many things have happened for a reason that have affected us today and will in the future to. The invention of cars was another thing that affected us too. They came to be because one guy had an idea to try to make people move faster from place to place in less time. Now this was good because we could travel to distance cities and towns in less time then it would have took with a horse and buggy. Also with all inventions there is probably a downside to this as well. When cars run they need fossil fuels which are oil and gas. These fossil fuels when burned in the engine destroy the worlds atmosphere when the pollutants that are released.
Many things happened for reason. If it was about religion, beliefs, or just because someone hated someone else for whatever reason is was that they hated that person. Everything happens for a reason.