Anton Rubinstein
He wrote a lot of music, but although his compositions often started off with good ideas they often become rather boring.  His opera Tom the fool was not a success.  He was annoyed and wrote an article in a music magazine saying that it was not possible to write operas using Russian stories.  He criticized several composers who were writing music which used Russian folktunes.  This included the composer Mily Balakirev and his friends who were called The Mighty Handful.  He said that they had not learned how to compose properly.