It's always amused me how Lestrade became a much more prominent presence than Gregson despite Gregson being more favorably presented than Lestrade in STUD.

Seeing the dynamic develop between Holmes and Watson is such a delight. I'm especially weak to Holmes worrying that Watson will lose interest in his work if he reveals too much. It makes sense in the first place that someone as theatrical as Holmes would enjoy having an audience on tenterhooks and I have to imagine the lack of acknowledgement he's received for his consultations affects him, too, where his vulnerability to praise is concerned.