I have a good one. I'm a DM for my DnD group, we have like 4, so we play multiple times a week, but I had a worldbuilding moment done by one of my party. The country is being taken over by a wizard that was creating his own demons. The country's general has entrusted his strongest warrior to report to the party that the city they started in has been lost, the general staying behind to mount a resistance. The warrior was to deliver a task to the party before traveling to another land to gain assistance against the demon threat. However, the dwarf fighter in the party got into a heated argument with the warrior, insulting him and questioning his honor for running. As a result the warrior failed to bring in aid, and he became a boss for the party to fight after beating the Big Bad. The warrior reclaimed the city after the Big Bad was defeated and turned it into a utopia for the rich, just to collect money from them and steal souls from the poor.