In the perfect Follies in my head, Sally sings the song with feet firmly on the ground as a deeply felt torch song. Interesting point.
The other 3 Follies clearly represent epiphanies for the other characters: Buddy comes to realizes he loves a woman who will never love him, Phyllis realizes that she would be fine "if Lucy and Jessie could only combine," and Ben realizes that he a sham.
In the original production, it WAS more like it is in the perfect Follies in your head: Dorothy Collins's still, tortured torch-song rendition communicated Sally's acceptance that for all the years she had been with Buddy, she has been losing her mind while doing all the things enumerated in the song (drinking coffee, talking to friends, standing in the middle of the floor, dimming the lights), all the while losing her mind. But all those things were private madnesses she was admitting to, things Sally had kept from Buddy and her friends. Whether or not she would go on losing her mind was left unsaid, but the song was a song of psychological insight and clarity--and of acceptance.
For the past few years, however, we have seen the steady pathologizing of the supposed mental health of Sally's character. It started with the astonishing performance by Victoria Clark in the Encores presentation. But Clark's Sally was at least functionally psychotic: She got through the days bearing her burden...everything fell apart only when she got to the Weismann and actually saw Ben again and kissed him.
Bernadette's Sally is certifiable, from the moment she comes in and first opens her mouth. She seems like the chorus girl who went batty, the one everyone in Phoenix whispers about: "Poor thing, she used to be a dancer in New York." "Her husband cheats on her, you know." "Poor thing..."
I think she's one of those actresses (whom we love) who has become un-direct-able. She revs up and does what she does, and it's so-so-so-Bernadette that everyone says "Oh-it's-so-wonderful!" but no one is able to help her exercise taste and restraint: no one is able to stop her from sinking into overacting, over-pausing and maudlinly crying instead of making the audience cry.