Tear jerking plot twists hit BECAUSE it's like a car crash. The story stops to get your attention. Like in One Piece, the Marineford fight was a total rollercoaster. Whitebeard shows up to stop Ace's execution... fails... goes nuts wrecking Marines... dies anyways. A LOT of people die in the biggest fight One Piece had seen yet. You felt a lot of stuff.... the weird comedy... actually accented just how nuts the stakes actually were. Everyone knows it's a fight to the death... including the people who REALLY aren't ready for that. Big players want to fight... and everyone else gets stuck with it. Which is a super dark moment specifically to illustrate how serious it is.
You went away not on a high... but dreading the next fight. But you knew things had happened that MEANT something. The DBZ-level fight was just the story telling device for a rather emotional story. This was a two-sided FAFO scenario where both sides had been aggressively posturing and now this was the breaking point.