One of the articles in the series inspired by Stella Gibbons's novel My American describes Amy's Lee's nightmare experience in the form of a horrible recurring dream in which she is invisible to the crowds of Hurrying People who stream past and ignore her no matter how hard she tries to attract their attention. She also has a few daytime experiences that trigger memories of her dream.
Amy Lee is not alone in sometimes feeling like a ghost in a world full of real people.
Examples from real life
It is not just fictional people who sometimes feel invisible.
The former friend who is featured in the story about the sultanas and the fox cub told me that she often had a sense of standing apart and invisible while crowds of people streamed past. Another friend who was involved in some of the other synchronicities in that article had similar experiences.
I haven't had any nightmares about Hurrying People myself, but I have experienced this phenomenon on a few occasions while out walking. This comes from one of my articles about energy vampires: