It’s interesting, @lalaurelia - when you think that everything we saw was the product of Jim’s subconscious. Let’s have fun with some meta and analysing the bejesus out of the costumes! :)
First off - the fact that Barbara is Jim’s guide on this little jaunt through his subconscious suggests that she still plays a starring role in his psyche, whether he would ever admit to it or not.
Not only does she give him the key that takes him to his deepest insight: the encounter with his father, she also challenges him and calls him on his bullshit. Right after Jim’s 1950s idyll with Lee and their imaginary children crumbles, we have this.
Jim: Open the damn gate, Barbara. I need to get back to them. To her.
Barbara: If you’re so desperate to have Thompkins and the two kids, why are you in that crappy apartment playing private dick?
Jim had the chance to have Lee and the white picket fence and scraped knees fantasy over and over again. She repeatedly asked him to leave town with her. She wanted to maintain contact when he was in prison. He could have contacted her immediately after he escaped. He could have talked to her when she showed up again and she’d have dumped Mario with unseemly haste.
He did not do any of these things.
In reality, Lee had to do virtually all the work in the relationship - not matter how much noise Jim makes about it. He had the chance to have his 1950s life. But part of him prefers to play private dick in his crummy apartment - and he knows it.
That’s reflected in the nature of the fantasy he constructs. It looks staged - like a representation of a happy family that he’d have seen on TV. Look at some of the lyrics to the song that’s playing in the background of that scene.
If you are but a dream
I hope I never waken
It’s more than I could bear
To find that I’m forsaken
If you’re a fantasy
Then I’m content to be
In love with lovely you
And pray my dream comes true
It’s all nice and pretty - but it’s fake. And it’s not just the setting, either. Even Lee is really an idealised and heavily edited version of herself here. Compare Jim’s Doris Day version of her with this dialogue in The Blind Fortuneteller, when they’re underneath the bridge - trying to solve the murder of Jerome’s mother.
Jim: But, uh, let’s not make a habit out of it, okay? This is no place for a lady.
Jim: What do you mean, “ha”?
Lee : You’re a hypocrite. You say you want a strong woman to share this crazy life you’ve chosen, but when push comes to shove, you want me to stay home and bake cookies.
This fantasy not only proves Lee right, but shows us that he’s never really moved on from this way of thinking. His subconscious, in the form of Barbara, serves him the unpalatable truth.
Another piece of dialogue that really interested me was this. Right at the end of his hallucination, when Jim nervously waits to see what’s on the final floor, hallucination Barbara offers him some comfort.
Barbara: Don’t be scared. It’s not easy to face who you really are. I should know.
Jim: Do you ever wish you were the person you used to be?
Although Barbara’s obsessive ‘Jim and I share a darkness’ became a bit wearying - she’s not really wrong. They both have a temper. They’re both willing to resort to violence to vent that rage. They both use alcohol to self-medicate. They’re both quite bad at being alone: Barbara returns to Tabitha after Jim’s rejection, and Jim not only lets Lee do all the chasing, but he latches on to Valerie Vale to alleviate his loneliness. There’s even a physical resemblance, I think: blond/e hair, blue eyes, strong jaw.
So Jim - though he’d noisily deny it - does deep down acknowledge a sort of kinship there: an honesty that he seemingly can’t achieve with Lee, because he insists on setting her on an angel of the hearth pedestal, instead of engaging with who she actually is.
That’s also visible through the costuming choices. Barbara’s role as guide means that she changes outfit here as the context demands - elevator girl, etc. She’s a chameleon - which is itself interesting in considering how Jim sees her.
Jim’s vision of Lee looks nothing like Lee - desexualised and domesticated in a prim twin-set and pearls:
Even the shape is dowdy - which you can see here as she waits for Jim to pull out her chair (it’s like MST3K’s A Date with Your Family)
Desirable, inquisitive Lee with her taste for danger is transformed into the safe and nonthreatening figure of the stereotypical 50s housewife - smiling and passive. They could have gone much prettier than this and still yelled domesticity - but they deliberately steered into frumpy.
You could argue - if you wanted to carry the costuming analysis further - that the early 60s choice for Barbara points to her as someone that’s far harder for Jim to handle. The trappings of femininity are all still there - but the look of the early 60s signals the arrival of potentially disruptive and subversive ideas that will directly challenge the 50s idyll that Jim has told himself he longs for.
The gold/metallic parts of her outfit point to money, and remind us of Barbara’s wealthy background and high society tastes: the look suggests power as well as sexuality - someone who is aware of who they are and knows how to use it.
In short - Jim could do with dissolving some of that weird hallucination powder into his tea every morning. He might be a happier and more self-aware man.