I would advise my young colleagues, the composers of symphonies, to drop in sometimes at the kindergarten, too. It is there that it is decided whether there will be anybody to understand their works in twenty years' time. ↗
Although, I am proud of all my Symphonies as they all have something special to say, my particular favourite is the Fifth. As the great Mahler expert Donald Mitchell said that if Mahler had written another Symphony, it would have been my Fifth! ↗