What debilitating effects did WW2 have?

WWII was a great loss to the world. Trillions of dollars were lost in creating the weapons of war—these dollars could have gone towards rebuilding the consumer economies of Europe after WWI. All of the major combatants lost significant numbers of both soldiers and civilians, and it is impossible to predict what these people would have done with their lives in the future. The practice of carpet bombing led to the leveling of many major historic cities. The war led to the expansion of the Holocaust as Hitler found more Jews and Slavs in Eastern Europe to exterminate. The atomic bomb took one of the greatest sources of energy ever discovered, the atom, and turned it into a weapon of war that would shape the postwar relationship between the United States and the Soviet Union. The Soviet Union felt threatened enough to maintain a buffer system of Eastern European satellites while the United States continued its military spending for the next forty years and fought many proxy wars with the Soviet Union in Vietnam and Afghanistan.

There are two (of many) ways in which one can understand the debilitating effects of The Second World War on the world. The first of which is an appreciation of the economic and infrastructural impacts of the conflict on many nations, and the second is an understanding of how WW2 affected the fate of global politics in setting up The Cold War. For the former, there were several nations whose land, economies, and people suffered dearly by the end of the conflict, and there are others who came out of in a state of immense financial prosperity. The main examples we can point to on either side of this spectrum would be The Soviet Union and The United States.
The Soviet Union suffered greatly by the end of the war, with an estimated 23,000,000 people dying over its course, and the majority of Eastern Europe in a state of ruin. The United States on the other hand, rose from the ashes of its former depression, seeing a surge in factory production that nearly completely eliminated unemployment in the nation and elevated the US into an emerging global superpower. It is these conditions that each of these nations find themselves in that sets up the tone of the peace conferences which concluded the War.
During the peace talks at Yalta, the United States was too pre-occupied with its continued war in the Pacific and thus stood by as the Soviet Union extended its influence across Eastern Europe, establishing communist governments in nations such as Poland, Romania, and Czechoslovakia. In addition, the Soviet Union felt like, due to the immense amount of sacrifice of Soviet lives, the nation was entitled to more demands in the negotiations, much to the chagrin of the US and Britain.
It is these uneasy tensions established as early as Yalta which began to sew the seeds for early Cold War relations between the superpowers of The Soviet Union and the United States. In addition, most of Europe's landscape was war-torn and in a deep amount of economic misery, and it is through the financial assistance of the American Marshal Plan that many western European nations were able to bounce back and recover from the war in a shorter amount of time.