Seirei no Moribito/YMMV

Non Sequitur Scene - About halfway through the series, they take a break from the main plot for a lengthy discussion from a blacksmith about a theoretical perfect weapon which would enable its wielder to defeat an opponent without killing him. Shortly thereafter, Balsa finds herself stalked by an enemy she once defeated, who now imitates her clothes and methods in a He Who Fights Monsters effort to 'become the tiger.' Balsa is pushed further and further over the edge and eventually must fight him to the death despite her vow never to take a life. With her shiny new weapon in hand, she delivers what she thinks is a fatal blow, and walks off... only for the witnesses to discover that the man is alive and unharmed but now amnesiac. This has no bearing to the main plot and is never mentioned again.
Needs More Love - It's a shame how far under the radar this show is.