I have seen many times in anime and manga that a character eats his/(mainly)her lunch in a toilet.
Why do characters in anime/manga eat their lunches in restrooms? Is this kind of behaviour a meme in Japan or due to some special culture in Japan? How common is this practice in Japan?
Besides, I noticed the characters involved in such behaviour seem to have one thing in common: they are introvert and don't have many friends. I am not sure whether this common trait have anything to do with their choice of restroom as a place for lunch, though.