Why do you start mirroring the person you're talking to?

If your friend crosses their legs, watch your own a minute later - you probably just did too.

In conversation we unconsciously copy each other's postures, gestures, and mannerisms. Simply seeing a movement nudges your body to repeat it, and that quiet matching tends to make the other person warm to you a bit, often without either of you noticing. The mimicry is well established; the liking boost is real but small, so treat it as a gentle nudge, not a guaranteed lever.

At a coffee shop you and a new colleague both end up leaning on one elbow, sipping at the same beat. Neither of you planned it, but the chat feels easy and you walk away thinking the person is nice.

Loosely matching someone's body language can build rapport, but keep it subtle - obvious copying tends to backfire.

In an interview or a first meeting, gently echoing the other person's pace and posture can make you feel more familiar, as long as you do not overdo it.

Chameleon: it changes to match its surroundings, and so do you.

Learn the idea and practice English at the same time.