baking something sweet and delicious at another person's house, then after eating your fill, leaving all of the remainder. Meaning you then do not have a tummy ache from eating too many sweets and they, inevitably, do.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.