Sherlock: 10 Worst Things Sherlock Holmes Ever Did
6. Indirectly Leading To Mary's Death
Sherlock's destruction of John's proposal to Mary was undoubtedly a roadblock, but eventually, the pair ended up getting hitched. Unfortunately, there was another twist in the pipelines, as it turns out Mary was not who she claimed to be, as she harboured a dark and dangerous life as a former assassin. That wasn't even the end of Watson's shocking heartbreak.
The episode "The Six Thatchers" ended with a showdown in an aquarium, as Vivian Norbury - a disgruntled secretary responsible for the episode's shenanigans - pulled a gun on Sherlock and Mary. In response to this, Sherlock did what he does best and deciphered information from her, mocking her and attempting to destroy her confidence.
After this - as you might expect from someone wielding a gun - she took action and shot a round at him, which Mary jumped in front of. It was a shocking moment and made all the worse as Watson arrived on the scene to say goodbye to his loving wife.
Sherlock didn't fire the gun or intend for this to happen, but he caused it through his ego and over-confidence.