"You’ll find another."

 (Sherlock meta by Ivy Blossom)

["Nothng more than a distraction, a little scrap of ordinariness for you to impress, to dazzle with your cleverness. You'll find another."]

This lie, identified specifically as a lie, is the greatest statement about what John is to Sherlock. Not a distraction, but the person who finally allows Sherlock to find purpose and focus. While John may appear to be ordinary, we know that he is not; he is entirely singular, the only person who could fit perfectly into the hole in Sherlock’s heart and life and let him heal.

Believing that impressing and dazzling John with his cleverness is enough was Sherlock’s single greatest mistake. He misread his role in John’s life as merely entertainment, something that could vanish and miraculously, dazzlingly reappear without consequence. But John isn’t dazzled by Sherlock. John admires him, respects him, trusts him, and would gladly sacrifice himself to keep Sherlock in the world, because he believes without question that Sherlock deserves all of the faith John has placed in him. John believes that Sherlock has the ability to make the world a better place, and that the most important thing he can do is to sure that he does. John is far beyond dazzled by Sherlock; John loves him and believes in him with his whole heart.

Sherlock will never find another John. There is only one.