I heard an interview with the main actor who said that the film was not intended to be a horror movie but he himself would describe it as mental horror. I strongly subscribe to that.
It is not clear why he travels to this place, but everything there is monotonous, no bright colors, no honest smiles, nothing personal. Everything is ordered and everyone seems to be satisfied living this kind of life. Our "hero" though from the beginning seems to be misplaced and feels it himself.
What makes this film so important and good is the remarkable similarity to life in many large cities or even countries nowadays. You have to function, you are not supposed to let your colleague know your weaknesses, you show off on your wealth, your car, etc., and most of all you lack the true love of life that children have. Naturally, in this film you see neither children nor old people - they simply do not fit in a society of strong workers.
I would recommend this film to everyone - and make sure that this utopia does not come true!