And the Samurai was dispatched by his employer to execute the employer's long time enemy. As the Samurai, after a brief sword fight, prepared to take the last fatal beheading blow, the enemy looked sternly at the Samurai and spit in his face. The Samurai sheathed his Katana, turned and walked away.
Few people would understand why, so here lies the answer. The Samurai lived by Bushido, The Code of The Warrior, which held that no Samurai should let emotion play into the work they did as Mercenaries. When the Samurai was spat upon, he became angry, and by the Code of Bushido, was forced to turn and walk away.