all wars are ended forever, so that's out. and something so extreme would last MUCH longer than "a year or two." an effect that big would go through multiple generations and serve as a huge reminder to humanity for decades to come at a minimum. friggin' 9/11 lasted longer than "a year or two" and it's nowhere near the level being asked here. humans change depending on their circumstances, so whatever circumstances are needed to create such a situation will greatly affect them and that "human nature" will be changed. like it always is.
and if it's perfect then it's not boring. conflict between individuals wasn't removed. you're completely misunderstanding how a utopia works dude. >_>;
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"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.