Yesterday, I was considering the first time we meet John Watson, as he tells Sherlock Holmes that "I object to rows because my nerves were shaken." Then today, on a totally separate quest, I came upon these words, "Again I had an opportunity of asking him a point blank question, and again my delicacy prevented me from forcing another man to confide in me."
John Watson cannot bring himself to ask his room-mate what his occupation is.
Even in Victorian times, this hardly seems like a breech of social protocol, especially if said room-mate is actually conducting business within your shared rooms. And, as always, Watson gives us something about himself that passes muster in the flow of a narrative, but considered by itself brings up real questions.
Was it his delicate manners or his delicacy of health that prevented him from asking? In the modern era, a man who had endured what Watson had might be quickly understood to have suffered some form of post traumatic stress disorder. But even that seems like it might not account for Watson's seeming reluctance to be even so harmlessly assertive with, as he says, so specifically, "another man."
Telling your occupation isn't usually a confidence, unless it's something society usually frowns on. Might Watson have added a red herring or two in that visitor list to prevent his true thoughts about Sherlock Holmes at that time from becoming apparent.
One thing a lot of folks used to the more traditional Sherlockian study might not fully appreciate is the way fan fiction has studied the minds of Sherlock Holmes and John Watson, and continues to do so. When trying to get a feel for a whole personality, it is fine to call out this characteristic or that, but putting the whole of a person through scenario after scenario, feeling out how they might react in this situation or another . . . well, its almost like the experimental method using the personalities of Holmes and Watson as lab rats in an assortment of mazes.
One can test how well one knows the characters and build upon that knowledge as one writes, going "this seems right," "this doesn't seem right," testing and re-testing with betas and reader comments, moving on to new scenarios based upon what was learned in other fic-scientist's scenarios. One could take a simple sentence, like the one I fixated on above, construct a situation to test Watson's "delicacy" at that point in the relationship, and let scenes play out until one of them hits the mark and shows us true Watson, bringing out potential backstories and feelings behind that line.
As with any Sherlockian scholarship that doesn't involve Conan Doyle and history books, exact, unarguable results are near impossible -- which is why the great game of Sherlockiana has lasted as long as it has. (Much like Ripperology which, with a slightly more solid Canon of evidence, continually produces results just as hazy as anything to do with Sherlock.) The fun is in coming up with your own answers to those unanswerable questions.
And Watson has left us with so many, probably because he was just too "delicate" to be straight with us. (Pun, unintended, but left in like it was.)