Five things Dr. John H. Watson thought but never said
1. Watson never let Holmes know just how much he really worried about his friend's health. There were times he thought about switching Holmes's cocaine with powdered milk. There were also times he thought about switching it with strychnine.
2. When Watson was in Afghanistan, one of the Pathans where he was stationed often went about singing a local folksong. Watson never had much of an ear for music, so he was surprised to find himself whistling it at odd moments. In time, he learned the lyrics well enough to sing them with gusto, much to the shock of his superior officer. When he found out what they meant, he never uttered them again. Even now, sometimes the tune still niggles at the edges of his consciousness, but he doesn't dare to whistle it, because with his luck Holmes would know it.
3. Watson thought Mycroft really wasn't smarter than Sherlock, not in any way that mattered. But there was no telling them that.
4. Quite by chance, Watson happened to run into Inspector Lestrade one evening. They made awkward conversation for a while, and then went to a pub, where Lestrade got horribly drunk and asked Watson if he thought anyone would remember him as anything but the policeman who always ran to Sherlock Holmes. Watson told him that Holmes had always said Lestrade was the best of the lot at Scotland Yard, which was true. That he himself disagreed with Holmes's assessment, however, was something Watson tactfully neglected to mention.
5. After Watson married, he moved from 221B Baker Street and set up house with Mary. He didn't feel bad about leaving, because he loved Mary and Holmes's fame meant that he didn't need Watson's help with the rent any more. But there were moments of disquiet. One came to him late at night, after Holmes had finally come to dinner for the first time. Holmes said little, ate less, thanked Mary graciously for dinner, and left, forgetting his hat. When he slid into his coat, the sleeve rode up, and Watson saw the puncture-marks.
That night, Watson thought very seriously about offering Holmes one of the spare bedrooms and office space in the parlor they weren't using. He almost mentioned the idea to Mary. Then he remembered everything she had been through already, and hesitated to bring more upon her doorstep. Holmes would wave off the idea anyway, and whatever would become of Mrs. Hudson? He knew Mary felt kindly toward Holmes, not only for what he'd done for her, but for what he'd done for a wounded young man fresh from the war, but shepherding Watson was enough; he couldn't ask her to help him shepherd Holmes, too. He knocked out his pipe and went to bed, and after breakfast and a quick stop at his practice, he set out for 221B to see what was afoot.