Angst? What Angst?: Averted. Characters react appropriately to the trauma and grief they experience, ex: Ace suffers PTSD from his death and torture at Pitch's hands, Sabo feels guilty about not saving Ace, etc.
Catharsis Factor: Ace burning Akainu to a crisp, killing his killer.
Fridge Brilliance: Pitch Black gets stronger when someone fears him. Despite sharing dark powers with him, Blackbeard never stood a chance.
Harsher in Hindsight: Jack promises to never leave Ace's side. Jack is separated from Ace, leading to the Marineford debacle, and again when Ace is captured by Pitch.
Nausea Fuel: The descriptions of the Black Sand moving under Ace's skin.