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.
YMMV: The Night's Dawn Trilogy
Canon Sue / Jerk Sue: Joshua Calvert is arrogant, irresistible to women, a starship captain, and finally banishes the possessed. He has unfortunate elements of this trope, but thankfully the fact that there are so many characters means that this needn't get in the way. Nevertheless, some people find him irritating - even Hamilton himselfcalls him a "prat".
Complete Monster: Oh God, Quinn Dexter... Guy made it his purpose to bring literal Hell-on-Earth living conditions to as many people as possible. Even the possessed are scared as piss of him.
In the first book, Laton, a Serpent (born-Edenist who rejects Edenism), is the galaxy's Big Bad since before the series started, having used his considerable skills and resources to destroy a habitat with a biotech virus, in order to facilitate his escape from the authorities. That got him named an "enemy of all humanity" by the Confederation government.
The Light Bringer mages, Omutan board of directors, the Black cartels who deal in antimatter, as well as most asteroid independence parties are presented as this. Humans are still bastards, after all...
Nightmare Fuel: Possession. The Melange. The Beyond. Also, being a ghost. If you don't want to give up your mortal life, you spend an eternity in the Beyond, where 5 minutes feels like an eternity, all the other souls are screaming to get out, and when you do get out, the souls in the Beyond compel you to open up bodies for possession by souls from the Beyond.