A high-quality relationship in fiction isn't just about two people falling in love; it’s about how they exist within that love. It’s the difference between a whirlwind summer fling and a partnership built on mutual respect, emotional intelligence, and shared growth.
The "Can men and women be friends?" debate is the intellectual spine. The relationship quality comes from the timeline . We watch them age, date other people, fail, and succeed. The climax (the famous New Year’s Eve speech) works because Harry lists specific, mundane details he loves about Sally. It isn't poetry; it's observation. That is high quality.
You know the beats: Meet-cute, refusal of the call, the first date, the dark moment, the grand gesture. These are tools, but they are not the story. A high quality romantic storyline subverts, deepens, or earns every beat.