These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ho Yay: Light isn't even alive in this universe, and there is still plenty of fodder for shippers, starting with the way he wears Light's watch in "rememberance," strengthened by the quote "Light, it hurts... My heart-", and ending with his offering at Light's altar.
Moral Event Horizon: K crossed it when she slaughtered a village full of people with a virus just to decrease the surplus population, believing that too many people in the world would destroy the environment.
And if that weren't that enough, killing Maki's father really ticked Maki off big time.
The Woobie: L, Maki, and Near. Could even count as the Freudian Trio. L only has 23 days to live, Maki witnessed her father being killed, and Near just barely managed to survive bioterrorist attack in the village he once lived in.