Frustration

I went upstairs to finish watching a movie while Mom watched the news. When I came down an hour later, she was very upset. When I inquired about it, she said she was very mad at herself for not going to the celebration.
I told her we did go. I showed her the flowers she got and the new pin she got.
She had found the letter and couldn't remember going. I've got to throw away that letter as soon as I can.