Throughout "The Adventure of the Speckled Band," the reader is presented with the contrasting personalities of Sherlock and Watson. Whereas Sherlock is eccentric and sometimes unpredictable, Watson is level-headed and responsible. Sherlock's deductive abilities are unmatched, while Watson is astounded by the former's discoveries. By positioning Watson as a foil for Sherlock, the story accentuates the latter's extraordinariness.
This becomes evident early in the story, when Sherlock wakes Watson earlier than usual:
...I woke one morning to find Sherlock Holmes standing, fully dressed, by the side of my bed. He was a late riser, as a rule, and as the clock on the mantelpiece showed me that it was only a quarter-past seven, I blinked up at him in some surprise, and perhaps just a little resentment, for I was myself regular in my habits.
Here, Watson explains that Sherlock's irregular lifestyle habits clash with his own adherence to a responsible daily routine. In addition, his irritation at being awoken so early infuses this contrast with humor. This contributes to the reader's impression of Watson as an ordinary observer of Sherlock's idiosyncrasies. By juxtaposing the extraordinary Sherlock with the ordinary Watson, the story foregrounds Sherlock's nature as an eccentric genius.
