The good ending dismisses us with a touch of ceremony and throws a backward light of significance over the story just read. It makes it, as they say, or unmakes it. A weak beginning is forgettable, but the end of a story bulks in the reader's mind like the giant foot in a foreshortened photograph.
There is a great deal of busywork to a writer's life, as to a professor's life, a great deal of work that matters only in that, if you don't do it, your desk becomes very full of papers. So, there is a lot of letter answering and a certain amount of speaking, though I try to keep that at a minimum.