At least one per book, such as the bit in Runaway Elf where Sammy helps Elyssa move past the death of her father.
All of Sammy and Darren's interactions in Killer Cruise, their first significant time together after learning they are father and daughter. Particularly the end, where she decorates a pair of high-tops for him like Casey did for her.
Any time Sammy shows her caring, compassionate side, such as when she comforts Holly when her cardboard box is destroyed.
Hudson and Sammy's inter-generational relationship, with Hudson acting as Sammy's mentor, confidant and friend, is very sweet.