What I find the most interesting is what seems to be Ayu's commentary about her time in the music industry, especially by means of her lyrics and music videos. And by doing so reveals a lot of the symbolism hidden in plain sight, which seems to be widely used in her industry.
YOU - The video gives the impression that she's lamenting the time that's passing her by while she's trapped in a beautiful prison. She touches upon this again in the song immature, although with a greater sense of desperation.
A Song for xx - This song is fascinatingly multi-layered. On the surface it seems to be a teenager's angst-ridden display of emotions to a parental figure or even the audience. But I also detect a sense of sorrow at the realization of her label's true purpose for her. She knows that she's nothing but a means to an end for them, and she knows she's trapped with them until the end. She knows she can't trust anyone anymore. This makes her defiance in 2000 and her insistence in re-recording this particular song so much more poignant.
POWDER SNOW - This song is like the aftermath of A Song for xx. She's accepted her fate, now let her cry about the loss of her freedom as much as she wants.
WHATEVER - This is truly where the occult symbolism seems to begin. She's like a bird trapped in a cage kept in a frozen wasteland. She doesn't have the freedom to fly, but she can sing. And that is her strength and the hope that lets her fight (for her sanity, perhaps?)
Trauma - This song makes me think that if Ayu really is a victim of the music industry's infamous humiliation and abuse of their artists, she was too strong-willed to be completely susceptible to it. Instead of getting a broken, obedient dog, they only exacerbated Ayu's cynicism and her grim views on human nature. This song seems to me to be a reaction to mental abuse.
SURREAL - This music video is one of the most symbolic in Ayu's career. The Duty sex kitten is seen here as an alternate persona (ayumi hamasaki, the product?) being discovered by Ayu's true self. It hints towards dissociation. The lyrics seem to indicate that she is locked in an endless struggle between staying true to herself and falling prey to her baser instincts (MK Ultra programming?).
I am... - She's come to terms with the fact that she's fallen into an inescapable trap into the music industry. She seems to be channeling her anger and sorrow into creating a stronger, more confident persona. This is around the time we start seeing less of the reserved Ayu of old and more of the diva we know today. She seems to have created this persona to cope with the unimaginable strain on her sanity that life in her industry may have. She touches upon this more in Naturally.
RAINBOW - Another video with occult symbolism. The split personality that is said to result from MK Ultra. Here we see Ayu's detection of another personality and her attempts to reconcile the two. Or perhaps we see the stronger personality snuff out the one it sees as weaker and less useful?
Free & Easy - This is another video that uses strong symbolism. The perfect white walls in an insane asylum that indicate brainwashing (something similar was seen in Voyage, along with dissociation). Using Joan of Ark as a metaphor was very interesting. Like Joan, Ayu is being sacrificed for standing up for her beliefs. She strives to show us that we are all prisoners in beautiful cages, which she was able to see when she broke out of her own cage (just like Neo from The Matrix, lol). She, however, knows that she won't get a happy ending and accepts her fate with dignity. As long as she's shown other people the truth her sacrifice won't be in vain. This theme is also present in the song Duty, although presented in a different way and mindset.
ourselves - Perhaps Ayu's greatest video filled with symbolism. There isn't really anything I could add to what's already been written about it in this thread

. This video really captures the torture and humiliation that a victim of the music industry endures (allegedly, lol).
There's so much more I could write about, but I feel like I've already written quite a lot. Surely anyone who's read this far is exhausted, haha. Although Ayu doesn't seem to have suffered under the music industry as much as people like Britney Spears and Whitney Houston, she's also a much stronger person mentally. She hasn't had any major mental breakdowns or been addicted to dangerous drugs like cocaine. She seems to have always had a good head on her shoulders throughout all these years. However, as her lyrics and videos seem to hint at, that's no indication that the industry's methods haven't had their effect on her. She simply acknowledges her experiences and chooses to live with them without succumbing to despair. "I only make the choices I am ready to accept."
Some of the best symbolism in other lyrics and videos: Fly high, And Then, P.S II, kanariya, End of the World, Dearest, Endless sorrow, Because of You, About You, Moments, STEP you, Ladies Night, (miss)understood, alterna, 1 LOVE, Secret, GUILTY, Together When..., Marionette, Microphone, sexy little things, Don't look back, MOON, Do it again, Why..., BRILLANTE, Party Queen, reminds me