Enterprise S2 finale, where Duras keeps chasing Archer and attacking him, why does Starfleet not take him seriously? They just chase him off the first time, Enterprise just runs away the second time, and finally destroys them the third time.
They were going on an extended mission alone in hostile territory, letting themselves get beat up repeatedly was incredibly stupid. They should've destroyed Duras the first time he attacked them after the refit with Photon Torpedoes. Since they didn't when they had the chance, they ended up taking a lot more damage before they got in and wasted valuable repair resources they would need for their mission.