For people with jobs that demand a ceaseless happy face, Smile Mask Syndrome (SMS) reveals the darker side of obligatory cheer. Sufferers of SMS, primarily young women in the Japanese service industry, exhibit depression and physical ailments as a result of being forced to smile for hours on end.
This disorder was coined by Professor Makoto Natsume of Osaka Shoin Women's University, who noticed that some of his patients "had spent so much time faking their smiles that they were unaware that they were smiling even while relating stressful or upsetting experiences to him." (Wikipedia) The consequences of SMS are not merely psychological. Many sufferers develop physical symptoms from forced smiling, akin to repetitive strain injury, from muscle aches to headaches.
Author Tomomi Fujiwara believes the origins of this demand for constant cheerfulness trace back to the cultural shifts of the 1980s, catalyzed by the opening of Tokyo Disneyland in 1983. The theme park enforced a compulsory workplace smile, creating a ripple effect throughout Japan and beyond.