I have adopted Ignaz Moscheles as an ‘honorary Englishman’ so I found this short anecdote rather amusing. Of course, it is not side-splittingly funny in today’s terms but is a little bit of gentle humour. It is worth recording.
Ignaz Moscheles, the virtuoso, composer, and teacher, had one fault that we must say was not confined to him alone. In teaching he used frequently to forget the purpose for which the pupil was present, and instead of using every minute for the pupil's advancement, he would take up much time in relating his experiences and reminiscences, and telling about the different composers and notable people he had met in his long and busy life. And his pupils were oftentimes not averse to this, for besides being very entertaining, it occasionally concealed the fact that the lessons were not as well prepared as they might have been.
In one of his classes were Sir Arthur Sullivan, and the violinist, Karl Feininger . As they came to recitation one morning all the class was struck with the downcast expression on the face of the usually smiling Moscheles, and as the pupils came in each one would exclaim: ‘Goodness gracious, Herr Professor, what is the matter; are you ill?’ But never a word did they get in reply, only a wave of the hand toward the piano, as much as to say, ‘You are here to study music and not to pry into my feelings. Do not chatter to me; sit down and attend to the lesson.’
The last pupil to enter was Feininger, and he being Moscheles' pet pupil, felt brave enough to insist that the dear Herr Professor tell his anxious pupils what had occurred to so cast a cloud over his genial spirits.
"Well," said Moscheles, ‘I will tell you.’ So, with laboured breath he began: "I got up this morning I dressed myself I went to eat my breakfast there was no butter I sent my Dienstmadchen [maidservant] for some butter’ and then his voice burst forth in agony, almost in sobs, ‘and what do you think she brought it in? That butter was wrapped in a page of my G minor Concerto’. 
W Francis Gates, Anecdotes of Great Musicians (Weekes & Co., London,1896) (with minor edits)
 Karl Feininger (1844-1922), a German American pianist. Was also a performer and teacher.
 Ignaz Moscheles’ Piano Concerto No.3 in g minor (1820) is fortunately still extant. It can be heard on YouTube in its entirety, including the page noted above”