Duality
Duality is important in La La Land. The first time we see Sebastian, what we actually see is his reflection in the car mirror. And when we meet Mia for the first time, we think she is on a phone call. She isn't at all—she's just practicing for a role. And so each of our main characters first appears in a different aspect than their "true" self. Mirrors feature repeatedly in the film. The first time we see Mia hum her way into what would presumably be a first solo song, had her housemate not interrupted her, she is looking at herself in the bathroom mirror. Perhaps one could argue that Mia and Sebastian both contain dream selves, or selves who are propelled to reach their dreams, and these selves live alongside their day-to-day realities: serving coffee, getting stuck in traffic and even falling in love. Eventually the tension between these two selves becomes too much for the individual to bear.
The film sometimes suggests a destiny that we can't see. In "City of Stars," Mia and Sebastian sing "City of stars, are you shining just for me? City of stars, there's so much that I can't see. Who knows?" Even though the stars seems to shine brightly for them on that night, the opening lyrics points to a deeper knowledge: that they fundamentally don't know what they can't see.
And so it makes sense that these star-crossed lovers should part by the end. Their dual selves could only travel together for so long; finally the life they share—between their everyday selves—is torn apart up by the force of their bigger, individual dreams.
Cars and journeying
The film is set in L.A., where a lot of time is spent in the car. The prevalence of cars is more than just realism. When we first meet our protagonists, they are stuck in a very long traffic jam—as they are, symbolically, in their own lives. At this stage, to reach their dreams, there is still a long distance to travel. And when Mia goes to the party with her housemates early on in the film, losing her car seems to point to a larger truth that she doesn't yet have the vehicle to get her journey started.
Once Sebastian and Mia meet, the road seems clearer. Sebastian walks Mia to her car and helps her to find it by telling her to hold her keys under her chin. He is literally and metaphorically helping her to find her way on her journey. When 'Summer' opens and Mia is writing her one woman show, we see her jump into the car with Sebastian and race off. She's on the right track. However, it is equally significant to point out that just after racing off and turning right, out of shot, Sebastian has to reverse down the one-way street. And so this car journey suggests that the road isn't as straightforward for Mia and Sebastian as we might, at this point, have thought.
Identity
It makes sense that Mia and Sebastian struggle to find and clearly express their own identities. L.A. is a fast moving world and in order to be seen you have to get peoples' attention. But people tend not to pay attention when you're expressing what's really going on inside—which is often not so clear or instantly attractive. Mia's very first audition in the film is disappointing for that very reason. She's doing an emotional piece and is really "going there," but no one in the room seems to value what she's doing; she's interrupted for a phone message.
And so it is significant that Mia pushes Sebastian to call his club Seb's instead of 'Chicken on a Stick'. It seems that she wants him to take ownership of the club he dreams of having, to let go of the past and start anew, as himself. In the same way, it is interesting that Mia finally achieves success when she writes her own material. It's by speaking her own words in her own voice that she is able to connect with who she really is and what she wants.
Although the two characters hold dear the influence each has had on the other, in order to fully realize their own identities, they must let go of what's gone before: whether that be Charlie Parker, Ingrid Bergman, or, in fact, each other.
Romance
Although Sebastian and Mia's relationship is at the heart of La La Land, the most significant romance in the film is the romance they each have with their dreams. By the end of the film, it is a difficult and moving realization for both of them that their paths took them in different directions.
And because the story follows Mia's dream more conclusively, the romance must also be with L.A. and its movie making history. Much of the film is shot on location in L.A. and celebrates so many aspects of the city, from its traffic jams full of people chasing dreams to its pool parties, jazz clubs and vistas. It's where the Hollywood greats of the past made their work and drank coffee.
And so, perhaps it makes sense that Mia and Sebastian start their romance with each other tentatively—not wanting to accept that there's any chemistry between them. Maybe somewhere they know that they have little control over whether their romance will last forever. The romance they have with their dreams, though, can go on and on.
Nostalgia
The film nods to the classic era of Hollywood film, where musical numbers were big and fantastical—heightened spectacles, that came out of a character or characters' necessity to express their feelings. La La Land indulges the escapist past, and the film is littered with nods to that great Hollywood time: the film announces that it's shot in CinemaScope, a huge poster of Bergman adorns Mia's wall, and Mia and Sebastian spend their first date at Rebel Without a Cause.
Within the film itself there is also nostalgia for a lost time. Sebastian is infuriated that jazz as he knows and loves it is dying. This is why he initially rejects Keith's offer to join his band—because he doesn't want to be a part of anything that dilutes the tradition. Commenting that his favorite old jazz club, the Van Beek, is now a samba-tapas joint, Sebastian muses that the "joke's on history." He wants to revive jazz by setting up his own club, in a style true to the old greats.
Mia worries that her one-woman show is "really nostalgic." Sebastian quickly responds: "that's the point." The film celebrates the act of reveling in the past.
And of course the film ends on a note of nostalgia, when Mia and Sebastian look and smile at each other at his club, Seb's. We already know that Mia is wondering what could have been—we've seen her retrace the past with Sebastian in the role of lover and then husband.
Home
Where do our protagonists feel at home in La La Land? Mia lives in many different places over the course of the film. First she shares a house with three housemates, then she lives with Sebastian in his apartment, then briefly moves back to her parents' house in Boulder City, and finally we see her in her own house, with her husband and daughter. But home seems to be the place where Mia's dreams are protected. In fact, after her one-woman show, discouraged and disappointed, she rejects the home she shares with Sebastian. She talks of going home to her parents. The shift here is obvious, particularly to Sebastian, who simply answers "but this is home." It was home while she was encouraged by him, while she was inspired to write material to help her reach her dream—but not anymore. Not after she starts to lose faith in her dreams, not after Sebastian doesn't show up to see her perform.
Sebastian is so focused on his dreams when we first meet him that he's failed to provide himself with a home. Pointing out all the unpacked boxes, Sebastian's sister Laura muses "do you think mom or dad would call this a home?" The point is that Sebastian's home is in his dreams—the boxes will be unpacked when they are unpacked in his club, when he "gets home."
And so, although the lovers find a temporary home with each other, neither lands home until their dreams are realized; home is in themselves, in the people they want to be. And so by the end it is moving for them to share that glance and smile with each other—acknowledging the home they left behind, they then move on again to their separate homes, on their separate individual paths.
Circularity
An important theme in the film is the interconnection and larger patterns that shape life. Even though Mia and Sebastian are individuals with their own particular dreams, love, hopes and fears, there are greater patterns at work, and their lives are just two of many.
The film begins with a traffic jam, and Mia finds herself in a similar traffic jam at the end of the film. Despite the journey we've been on with Mia and Sebastian by the end of the film, L.A. is unchanged - there are still people chasing their dreams and trying to get where they're going on the freeway. Life moves on and repeats its patterns; it's just the individuals that change. Of course we also see Mia at the start of the film as a barista in a coffee shop—the same one she goes into at the end, as a customer. And presumably some day the barista who serves her will one day move on and be replaced too.
It is also thus significant that Mia and Sebastian retrace the steps of the actors in Rebel Without a Cause. It is their particular romance that we are watching, but their paths have been trodden before, and—it is suggested—will be trodden again.
The structure of the film also reflects this circularity. We start with winter and roll all the way back to winter again. Whatever is going on for Sebastian and Mia, the seasons are constant and keep moving, whatever the weather.
