Must have arrived too late for inclusion -
While Thais are known for their gracious smiles and bawdy humour, King Bhumibol alone is serious, gray, and almost tormented by the weighty matters of his realm. .....he seemed never to be seen smiling, instead displaying an apparent penitential pleasurelessness in the trappings and burdens of the throne.
For the Thais, this was a sign of his spiritual greatness. In the Buddhist culture, either a smile or a frown would indicate attachment to worldly pleasures or desires. Bhumibol's public visage was unfailingly one of kindly benevolence and impassivity. In his equanimity he resembled the greatest kings of the past, the dhammarajas of the 13th-century Sukhotai kingdom...."
From The King Never Smiles