You know the old saying, 'smile and the world smiles with you'? And have you found that to be true a lot of the time? And are you one of those people who find it impossible not to 'catch' a yawn? In fact, you may have noticed that a lot of our body language is infectious – especially with those we are closest to. Well, there is a scientific reason for it, y'know! Our brain contains little cells called mirror neurons and it's these minuscule message carriers that are r