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.
Harsher in Hindsight: In On A Pale Horse, Lachesis defends Fate's meddling in Zane's life by saying that "all mankind will be damned" if they don't meddle. Come For Love of Evil, we learn that Satan doesn't actually intend any such thing. Quite the opposite actually. His bid to claim God's power is motivated by a desire to stop people from being damned unfairly. The idea that the forces of Good may have actually been preventing a desirable outcome (and unwittingly subjecting countless innocent souls to damnation) by their interference is some pretty serious Fridge Horror.
Idiot Plot: The resolution of the plot in ...And Eternity only happens the way it does because Satan and the Incarnations are adhering to rules that are expressly referred to as a game. Every person involved in the system (the Incarnations except for God, who's effectively out of commission, plus Luna, Jolie and Orlene) has the same objective: dethrone God and fix the rules for the afterlife. Furthermore, they agree on what fixes need to be made. Nonetheless, Satan tries to stop the other side's plan and force them to capitulate to his leadership, not because his ego is on the line, but because he's supposed to play the game.
Retcon: The change in how Satan is presented to the reader from a clearly wicked and unrepentant villain to a sympathetic Anti-Villain who is Necessarily Evil may have been planned all along (since the signs of the latter characterization appeared in book five, well before the author decided to extend the series). Or, since Anthony only included this fully after his readership clamored for him to continue the series and to see things from Satan's perspective (which by its very nature would require casting his actions and motives in a different light than the heroes saw them), and this led to the character becoming popular, he may have altered his original view of the character. But either way, the Retcon itself works well upon re-reading the series later, particularly in how the later characterization makes scenes common to all the books look when the reader later sees them again from Satan's perspective. Even lines and actions which seemed reprehensible upon first reading still fit the sympathetic portrayal when the later-revealed thoughts and motives behind them are taken into consideration. (There's also the implication that said actions and words were either Parry indulging inplaying up the stereotype, or a case of Then Let Me Be Evil from which he later recovered, but this is much more ambiguous and up to the reader to decide.)
Tear Jerker: Fate having to comfort Norton's successor/predecessor, a six-year-old boy.
Also, a previous Chronos being broken at realizing that from the POV of Niobe, the woman that he had loved for 35 years, they are only meeting for the second time.
Orlene meeting God, except God is so narcissistic that He does not react to anything anymore.