Body language, not facial expressions, broadcasts what's happening to us http://goo.gl/th63J
Expressions numbered 1,4,6 show tennis player's face on losing a point; expressions numbered 2,3,5 show a player after winning a point). Tests show that those looking at facial expressions alone cannot determine what the true emotion is.
If you think that you can judge by examining someone's facial expressions if he has just hit the jackpot in the lottery or lost everything in the stock market -- think again. Researchers at the Hebrew University of Jerusalem and at New York University and Princeton University have discovered that -- despite what leading theoretical models and conventional wisdom might indicate -- it just doesn't work that way.