Our grins are not as simple as they seem.There are a myriad diifferent ways to smile-and some of them can conceal some less than happy.

Of 19 different types of smile,only six occur when we're having a good time .The rest happen when we're in pain,embarrassed,uncomfortable,horrified or even miserable.A smile may mean contempt,anger or incredulity,that we're lying or that we've lost.

While genuine,happy smiles exist as a reward for when  we've done something helpful to our survival,the non-enjoyment smiles are less about what you're feeling inside and more about what you want to signal to others.

1.duchenne smile

The first steps to decoding this multi-purpose expression came from the 19th Century neurologist Duchenne de Boulogne.In all Duchenne went on to discover 60 facial expressions,each involing its own dedicated group of facial muscles,which he depicted in a series of photographs.

In the most famous of these ,an unlucky man has his face contorted into a broad,toothless grin.He looks idiotically happy,with his cheeks pushed up and crow's feet around his eyes.

It's since become known as the felt or Duchenne smile and it's associated with genuine feelings of pleasure and giddy happiness.

2.fear smile.

Though we don't tend to associate smiling with feeling fearful in humans,there are some hints that the fear smile may have lingered on .In babies,a broad grin can either mean they're happy or distressed and studies have shown that men tend to smile more around those considerdered to be higher status.

3.miserable smile

The miserable smile is a stoical grin-and bear -it expression-a slight,asmmetric smile with an expression of deep sadness pasted over the top.

4.the dampened smile

The dampend smile is an attempt to control an automatic ,happy one.Intriguingly,this discrepancy even stretches to the waysmiles are typed:with a flat mouth and squinting eyes,as opposed to dotted eyes with a curved mouth.

5.embarrassed smile 

The embarrassed smile is identical,though the two are easily distinguished-if not by the flushed cheeks,then the uncomfortable situation which usualy precedes it.

6.qualifier smile

The qualifier smile aims to take the edge off bad news,such as the receptionist's smile who explains that the next available appintment is in a year's time .It's perhaps the most irritating of all the smiles ,since it ofthen traps the recipient into smiling back.