In my current setting, even common civilized folk are usually taught that life and souls are sacred and immense sources of power, and that there are afterlives and Outer Planes based on alignments and moral values. They are told that the Material Plane is a sacred proving ground for souls, to prepare for their immortal purpose in the afterlife, and to die early is to die before reaching one's true potential, so striving to excel at their passions while alive is highly encouraged. Whether their passion is battle and they are destined to fight for their gods on exalted battlefields, or their passion is hospitality and they are destined to bake perfect hunnybutter cookies that reward other souls with heavenly delight, they all have purpose.
Everyone who is taught about religion and the Outer Planes is taught that Balance is paramount, though a person cannot usually reach perfect Balance themselves. Because of this, every alignment is taught as having a purpose, even evil, because evil provides the opposition to good, and causes discomfort that tests people and forces them to grow or wither. People who embrace evil are told, or convince themselves, that they will uiltimately have power in the afterlife. People who are not taught about religion, or don't believe in it, are in for rude awakening when they don't know what to expect upon death. Such wayward souls can be tricked into torment in the afterlife.
A baker may consider themselves true good (NG) and work towards bettering the world in the kindest way they know how, and a LE blackguard may sell their soul and become a purposeful villain, taking and commanding all they can to prove their power and earn rewards in both life and the eternal afterlife within the Nine Hells. The blackguard can defend his evil actions by stating he is a nemesis that challenges any "hero" which makes both of them aspire to greater power. He may not even kill a hero if he wins, just forcing that hero to increase their might and try again. After all, the villain needs powerful foes to test their own mettle against. This "Balance of Strife" is perceived by some to be a symbiotic engine of growing one's own strength, so non-murderous rivalries and vendettas are common among proud folk who oppose each other.
I made a choice to give all alignments purpose and opposition, so not everyone just wants to kill their opposition on sight. Corruption and redemption are very powerful motives in the world. A villain who kills a hero just sent that hero to a good afterlife and their just rewards. That can be a boon to their opposition, so corruption is a very valid alternate path to death. There are some who walk a peaceful path whose purpose is to help redeem their opposition, not just kill them, because what matters is alignment at death. If a villain is defeated, imprisoned, and reformed, that is a greater victory than just killing them and sending their soul to whatever underworldly afterlife they might be destined for.