It is like playing the violin. The piece is over, and it's gone. Writing is permanent. It is generally regarded as difficult to explain mathematics to nonspecialists. I give talks on problems, not in detail, but at a level that has a chance of reaching them.
Preparation is essential.
Every single word that I publish I write at least six times. In that first 1942, von Neumann-inspired book, Halmos established a style and perspective that have become signatures of his celebrated career. Halmos is a generally colorful character with strong, sometimes controversial, opinions. His conversation is witty, articulate and compelling. Some quotes illustrate these characteristics.