Nice opening scenes and opening shots can be very helpful to get the audience in the right mindset for the entire film.

Opening scenes are mostly symbolic but its function is to fine tune the mood of the audience ready to see the film. It’s like a appetizer does for a meal. It’s mostly a revealing, surprising and symbolic shot. Even if the audience doesn’t know the symbolic content of it jet, s/he will remember the scene while watching the rest of the film, like puzzle pieces falling together, s/he and will than understand what it stands for.