The stories and themes are very different, but I like the two for the same reasons -- these dramas portray what it's like to be young in a way that feels very real (although they're 2 different age groups: R1997 is more highschool whereas CIT is college), their female leads are extremely relatable, and both are "slice of life" dramas that still manage to have heart-fluttering, yet realistic, romance. Also I love the female lead's best friend in both :^p ! The two dramas use flashbacks in a way that makes the story more intruiguing, instead of redundant. Finally, both dramas are tvn, so they have that slightly indie, less polished vibe, and target a young audience without being too fluffy or flaky.
Spring Waltz is a classic, older dramas and one of the famous Four Seasons. Although CITT is a comedy, it has some darker elements that remind me of the classic Spring Waltz. They're similar in the sense that they male lead id cruel to the female in the beginning and ignores her, making life tough. Later in the drama, they both come to realize they made a mistake and fall for the female leads. Both can be intense and misleading.
Secretary Kim has similar vibes to the romanace and comedy, taking on a more refreshing approach of the typical bad/cold guy thrope. However, Cheese in the Trap incorporates more of the sinister sides of liking someone with a hard to deal with personally while Sceretary Kim is more in the romcom sphere.