In The 9 Lives of Shakespeare, Life One, Graham Holderness examines the circumstances around which Shakespeare wrote his famous plays and poems. Specifically, how and where he wrote, and what he was thinking. He writes that most people are interested in the "romantic idea" that Shakespeare wrote with a beautiful quill and scroll, in a secluded book-lined room. While we can some inferences about Shakespeare's writing habits, we have no actual knowledge about what they were like, Holderness writes.
The article seems to almost obsess over the fact that while we don't have his original manuscripts of the plays, we do have his signature on several legal, which apparently is a very big deal even though it doesn't provide us with any insight into his writing habits. The author does the same thing about a specimen of his handwriting that has been recovered. To me, it seems like a bit of an overkill to analyze the circumstances surrounding Shakespeare's writings simply based on a random piece of his handwriting.
Later in the section, Holderness overviews the two general (and very opposite) speculations as to Shakespeare's writing habits. Both go over every detail about what it was like for Shakespeare to write. One writer places Shakespeare writing carefully in the quiet countryside, while another writer believes he liked to write in the midst of the hustle-and-bustle of London, wandering the streets and writing at "break-neck speed." As Holderness cleverly concludes the first section: "Will the real William Shakespeare please stand up?"
The fact that it is possible for either of these completely opposite scenarios to have been the case makes it seem like maybe we shouldn't even try to speculate about what we don't know.