If you thought Gwi was wickedly attractive, then give The Ghost Bride a try (Lim Tian Ching there looks and gives me similar vibes to Gwi).

Couple dynamics between the main leads was quite similar. Both couples were attracted to each other but couldn't be together due to FL's (in)decision. In One Spring Night, past is holding FL back, in Search: WWW it's future.
Mature people, a bit sad, nostalgic feeling.

Relationship between the main couple has similar feeling (a bit like brother&sister, lots of playful teasing, not too much drama).