Positive effects of World War II.

The answer to this question is subjective. What one person lists as a positive effect could also be listed as a negative effect by another person. Germany's defeat was hailed as a great thing by the Allies, but plenty of Germans didn't see losing the war as a positive thing. I'd like to try and stay away from any kind of political answer in this question; therefore, I'd like to focus on beneficial science and technology that was developed during World War II that maintains importance in modern day times.
Nuclear energy was developed during World War II, and it culminated in two massive bombs being dropped. I'm not arguing that nuclear weaponry is a positive effect, but knowledge of nuclear fission has since created extremely powerful and relatively clean energy power plants.
Jet engines were developed during World War II, and worldwide transportation and commerce has been benefiting for decades.
Rocketry became a viable form propulsion. It was pioneered and turned into a reality through the V2 rocket program, but that rocketry knowledge later went on to be the basis of space programs around the world.
Computers emerged as a machine that could go through a tremendous amount of data. "Colossus" was originally invented as a way to speed up the cracking of the Enigma codes, and computers have since gotten smaller and faster ever since.
Superglue was invented. This was accidental, but I would definitely say it has had positive effects on the repair of kids' toys for years.
Radar really came to be a powerful tool, and it showed its potential in the Battle of Britain. Today it is used from things like checking the speed of a car to monitoring storm fronts.

The main positive effect of World War II was that Hitler's totalitarian regime was thwarted in its goal of European and, eventually, global domination. The same, of course, could be said of Japanese rule over the Pacific. This was a dramatic turning point in human history, even if it was followed by decades of simmering conflict between the Soviet Union and the United States. Another positive aspect of World War II was that its violence and destruction made the participating nations, led by the United States, try to set up a global order that would forestall a conflict like that ever again. The United Nations was the centerpiece of this system, which also featured such organizations as the (admittedly controversial) World Bank and the International Monetary Fund. Still, another consequence of the war was the collapse of European empires. The war proved the catalyst for the decolonization of Africa, as well as southern and southeast Asia. While this process proved bloody and difficult in many nations, more humans enjoyed the right of self-determination after World War II than at any time in human history. Hand-in-hand with this decolonization wave was the Civil Rights Movement in the United States. So World War II, despite being an unspeakable human tragedy, ushered in many changes globally that could be said to be positive.
https://www.history.com/topics/world-war-ii

The main positive effect of World War II was that the Allied powers won and the totalitarian regimes in Japan, Germany, and Italy were stopped. Another positive effect was that World War II effectively ended the Great Depression in the United States as people either went to fight the war or to work in war-related industries. World War II also brought an end to sharecropping as poor people in the South looked for opportunities in factories or fighting the war.
World War II brought about the United Nations; this was a stronger negotiating group than the League of Nations that was founded after World War I. The United Nations has provided a body for compromise that has prevented other world wars since then. World War II also led to scientific developments such as the rocket and atomic energy. While both of these were used during the war for killing enemy soldiers and noncombatants, both the rocket and atomic energy have had beneficial civilian uses. Another major social program to come out of World War II is the GI Bill in the United States. This allows soldiers to attend college either during or after their enlistment. This program has helped many people in the United States attend college when they might not otherwise have the money to attend.