It doesn't have to be completely realistic, but it has to be at least somewhat believable. If everybody in the anime isn't wearing shoes without a specific reason, now that is very unrealistic. Just like that Daddy part, how many kids really say it. And not only kids, teenagers also. So that is to the extreme unrealistic, like making everyone 5 meter tall, it's too extreme to make that word logical realistic.
It doesn't have to be completely realistic, but it has to be at least somewhat believable. If everybody in the anime isn't wearing shoes without a specific reason, now that is very unrealistic. Just like that Daddy part, how many kids really say it. And not only kids, teenagers also. So that is to the extreme unrealistic, like making everyone 5 meter tall, it's too extreme to make that word logical realistic.