Apparently, eating solo has become a new trend in Korea. Introducing "Honbap, 혼밥"
Eating Alone In South Korea Is The Newest Trend
http://www.koreaboo.com/buzz/south-koreans-are-starting-to-dine-solo-in-honbap-trend/
In South Korea, it’s more common to eat as groups of two or more than it is to eat alone, but a new trend is on the rise called ‘HONBAP’.
‘Honbap‘ is a combination of the Korean words for “alone” and “meal” and, as the word suggests, the trend involves the practice of eating alone. In Korean culture, it is seen as odd to eat alone and it is far more common to eat in groups or pairs. This new trend is, therefore, breaking with tradition and fits well with the fast-paced lifestyle of the young generation.
Apparently, Japan has the same trend. Called hikikomori (ひきこもり or 引き籠り)
https://timeline.com/japan-eating-alone-56c5fafe89ee