In his autobiography "In Memory Yet Green", Asimov had this to say about "Christmas on Ganymede": "I was trying to be funny, of course. I had this terrible urge to be "funny", you see, and had already indulged in humor in more than one story. Writing humor, however, is harder than digging ditches. Something can be moderately well written, or moderately suspenseful, or moderately ingenious, and get by in every case. Nothing, however, can be moderately humorous. Something is either "funny", or it is "not funny at all". There is nothing in between."