Edited:
I love every scene that involves these two. Let me quote one of the many I adore.
Accident scene: One of my favorite scene is when Dev tells the stories of his childhood to Sona, to keep her awake. Especially the one where he says tearfully "tumhe pata hai, uss din is ladke ne apna bachpan khodiya tha" with so much pain in his voice. Hearing that Sona moves, winces with pain and cries too. He asks her "Bahut dard ho raha hai?"
Yes. The pain for her at that moment was not just physical but emotional too, the pain that got transmitted from Dev. She felt the pain that he felt at that moment. This was one moving moment for me in the entire beautiful accident sequence.