Hello all, interesting topic we have here. As far as i know, Chopin had some pieces he was more fond of. The op. 25 no. 1, and the op. 64 no. 3, are truly from his beloved works, but there were more. Chopin really like his etude op. 10 no. 3 (tristesse), and once in a lesson with his student Guttman, Chopin remembered his beloved Poland, and he once said that he didn't write anything so beautiful until then. Another one of Chopin's favorite pieces by himself was the Allegro De Concert Op. 46. Some say this was supposed to be the beginning of the third concerto, but it was published as a piano solo, and Chopin used to say that this is the first piano piece he will play when coming back to free Poland (which of course never happened). Another favorite of Chopin, was the waltz op .34 no. 2 in A minor, the melancholique one. He once asked a friend of his which of the waltzes (which he just published in that time) he likes the best, and his friend said the op.34 no. 2 , and Chopin said to him that this his his favorite one, and than he bought him a cool cup of coffee.

that's from the tip of my head, if i will know of anything else i will write it, have a great day.