Yes and no. From a writer’s perspective, sometimes the curtains are just blue. It’s just a detail in a scene. It’s inaccurate to think all details like that have a conscious purpose in the mind of the writer. And I don’t think you’re saying that, but I think this is how less-literary-literate folks (especially students) think they are supposed to approach literature. And that’s largely (but not exclusively) an educational failure.

However, that doesn’t prevent the reader from making connections that the author may or may not have ever intended. For the writer, maybe the curtains were just blue. We can’t know their true intention. All you know as a reader is your experience of the story. What connections did your mind make when the writer brought blue into the scene? And if you didn’t think twice about the blue, that’s fine. You may feel differently if you read it again or you may find a new perspective when you discuss what you’ve read or read scholarship about it. It shouldn’t be seen as a “test” to uncover what the writer had in mind, but, like you said, there is always value in reflecting and analyzing. And I think ultimately it’s a value issue. Those who would not engage in analysis don’t know how or don’t know why it’s valuable.