Mad Max Fury Road. They defeat the tyrant, and get the control of the water valves. Then they open the valves and seemingly keep them open. One problem, how long is the water reservoir gonna last now?
Logan’s Run. The city dwellers are freed from the computer’s iron-fisted rule, and Carrousel. But their city is in ruins, and thinks to the computer providing everything. They don’t know how to live without it. The city dwellers are going to start dying off real fast.
Starship Troopers. The bugs weren’t actually aggressors, and the big one they caught at the end was just scared and sort of cute.
The main character started as a neutral, somewhat open minded guy and ended up a heartless war machine who drank the fascist kool aid and helped recruit new soldiers for their unjust causes.