A few days ago I shared a short clip and asked a simple question: what did you notice about the expressions in it? Plenty of you wrote back. Some were confident they had spotted a micro-expression. Most had actually spotted something else entirely, and that gap is exactly what makes this worth slowing down for.

The clip features Tamannaah smiling, and her smile is a good teaching case. Watch it frame by frame and you see something interesting happen in sequence. One side of her mouth lifts first. There is a small tilt, a slight asymmetry, on one side of the face. A beat later the other corner catches up and the lips settle into a straight, even line. By the end, both sides are doing the work together. That progression is what turns a half-expression into a complete one.

Why both sides matter

When a person genuinely smiles, the movement is symmetrical. Both corners of the mouth rise, the cheeks lift, and ideally you see involvement around the eyes too. That balance is part of what reads as warmth and ease to the people watching. A smile that stays lopsided, lifting on only one side, often signals something less wholehearted, a social smile rather than a felt one.

But here is the catch, and it is the part most people skip. You cannot judge asymmetry in isolation. Some people simply have a habitual one-sided smile. Others have a slight facial difference that pulls one corner more than the other. None of that means they are insincere. It means their natural, resting way of smiling is asymmetrical, and you have to account for it before you read anything into it.

The piece almost everyone misses: baseline behaviour

This is the single most overlooked idea in body language, and it changes everything. Baseline behaviour is how a person normally moves, speaks and expresses when they are relaxed and nothing unusual is going on. Their habitual smile. Their usual hand gestures. Their resting posture. You establish that baseline first, and only then do you treat a sudden departure from it as meaningful.

So with Tamannaah's smile, the right question is not "is one side higher?" It is "is this how she always smiles, or is this different from her norm?" Without the baseline, you are guessing. With it, you are reading.

Micro-expressions are not the same as this

Many of you said you had seen a micro-expression in the clip. Gently, that is probably not what you saw. Micro-expressions are something more specific. There are six core emotions that have universal facial signatures, and a micro-expression is one of those signatures appearing involuntarily for a split second, often when someone is trying to mask what they feel. A smile that builds over a second or two, settling into contentment, is not a micro-expression. It is an expression you can watch unfold in real time.

The distinction matters because the two work on completely different timescales and tell you different things. A micro-expression is a leak. A slow smile is a process you can simply observe.

How to practise this yourself

If you want to train your eye, start small and structured:

  • Watch a clip on mute, so words don't distract you from the face.
  • Note the person's resting expression before you judge any single moment.
  • Look for symmetry in a smile, and the sequence in which the corners move.
  • Resist the urge to label a fleeting movement a micro-expression unless it maps to one of the six core emotions.

Body language reveals patterns, not verdicts. Read for tendencies, hold your conclusions lightly, and let the baseline do its quiet work. Once you start watching faces this way, even a familiar smile starts telling you more than you expected.