"The Best Day" is a short story by Orson Scott Card. It appears in his short story collection Maps in a Mirror. Card originally published this story in his novel Saints (1983) under the pen name Dinah Kirkham.
This story is about a woman who is happy but is afraid that the happiness in her life will come to an end. She prays for eternal happiness and the next day an old peddler shows up selling plain things. When she asks him if he has anything for happiness he tries to explain that happiness is just a matter of taking joy in overcoming the difficulties in life. However, she doesn’t let him finish and sends him on his way. The next day a medicine man from the east shows up selling potions and bright cheerful things. The woman asks him if he has anything to do with happiness. The medicine man sells her an elixir of happiness. He says that one drink of it and your best day will be with you forever. She buys the elixir and takes it. After that she spends every moment of the rest of her life reliving one happy day from her past. As a result she misses out on the rest of her life.
Dinah Kirkham is the main character of Orson Scott Card's novel Saints. She is a fictional plural wife of Joseph Smith the founder of the Latter Day Saint movement. In the novel she is supposed to have made up the short story "The Best Day".