Is it just me, or do Sherlock and John both make the same funny face?
Mirroring. It’s where one person copies another person’s body language. It’s a (usually unconscious) sign of being in agreement/social harmony with them. A demonstration of empathic connection, basically.
We tend to mirror people we’re close to a lot—friends, family, lovers. It’s why old married couples sometimes start “looking alike” to us. Ahem.
Great stuff, by the way, for a job interview or flirting. People usually don’t even notice you’re doing it; they just start feeling more favorable towards you.
Also it’s darling.