The good doctor plays the sidekick to Holmes' self-obsessed hero figure. Watson is a lowly apprentice and live-in friend, who spends most of the book trying to solve a difficult case in his master's stead. Always on hand to stroke Holmes' ego, Watson is nonetheless intent on proving his own mettle by applying Holmes' techniques.
Watson's never-ending adulation, which is presumably meant to mirror our own understanding of the legendary detective, comes through most forcefully at the end of the novel, when Holmes arrives at Devonshire. Holmes announces that he meant for Watson to think he was in London, and a pouty Watson reacts: "Then you use me, and yet you do not trust me!" Codependent throughout, Holmes and Watson fill each other's needs. Watson provides Holmes with an ego boost, and Holmes needs Watson's eyes and ears to inconspicuously gather clues. Watson is awestruck by Holmes' power of observation, and Watson feels more powerful by association.