Cognitive dissonance, one might presume from the photos, but from the article:
The worldwide-exhibited Pink Series consists of photographs depicting an often expressionless man, wearing a shocking pink suit, in various metaphorical scenarios. In explaining the concept behind the series, the artist stated, ‘The Pink Man is my upset and alienated feeling towards the concept of consumerism which has been accepted simply and without consideration by Thai society. I feel that this system has enslaved us without our realisation. Moreover, we are being forced to act in the same way: there is a move towards uniformity.’
I can’t add more than that. The photos speak for themselves, though I’m happy to read the explanation. His work says that without his words.