The fact that John cancelled his date to be with Sherlock.
sorry but:
any loyal friend would cancel their damn date to look after their drugged friend.
that is not a declaration of love, that is a friend caring for another friend who happens to have been DRUGGED.
if he were to actually go on that date he’d be a fucking terrible friend.
I cancelled a date once. Had to look for my best mate who was drunk and was wandering alone.