But you are right, it's unusual behavior. It's part of the mentality, maybe... That's because any senseless demonstration of emotions could be recognized as a sign of not so smart person. This is the reason why typical official photo usually doesn't display any emotions.
Western politicians often smile because they want to show the voting public "hey I'm a nice guy, you can trust me".
But often it only just makes them look even more untrustworthy, like second-hand car salesmen.
![Grin](https://bitcointalk.org/Smileys/default/grin.gif)
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fmedia.salon.com%2F2011%2F01%2Fwhen_will_the_economy_finally_make_obama_smile.jpg&t=665&c=qLlaheNBE3JDZQ)