When you're writing a movie or a play and writing isn't going well, which is for me the normal condition - it's an exceptional day when suddenly I've got something and it's going well - you can call the studio or the producer or whoever is waiting for it and say, "I know I said I was going to have it in by the end of the summer.
In those vernal seasons of the year when the air is calm and pleasant, it were an injury and sullenness against nature not to go out and see her riches, and partake in her rejoicing with heaven and earth.