I've watched this movie more than 50 times. Still, I never feel boring. This movie is a masterpiece in the history of bollywood. No vulgarity, no nudity. This movie is a tight slap on those face who add extremely nonsense scene for popularity. This movie has the following fundamentals which they have followed until last scene:- Suspense, Emotions, Melodious and meaningful songs, track of the movie.
The movie switches in flash backs multiple times, which adds excitement multiple times. Everyone is excited to know what is going to be in the second diary after the first diary is finished. The song "Kaise mujhe tum mil gayi" can hardly ever be forgotten.
Overall every single scene is worth watching and worth appreciating.
Those who have given less than 5 stars, they too agree that this movie is literally very wonderful but I wonder some of them themselves have given 4 stars! May be they don't know counting of stars how they are selecting !