Journals and diaries are excellent resources for family history research.
Don't you wish your ancestors had recorded their daily lives and thoughts in a format that has come down to you as a treasured keepsake through the centuries?
I know someone whose ancestor left a journal written several hundred years ago. The writer describes the family's everyday life in difficult new surroundings, how they celebrated holidays, the writer's wishes for her descendants far in the future and much more. It is as if the writer knew it would be treasured and passed down through the generations, as it has been. It is a priceless heirloom.
Put yourself in the shoes of a great-grandchild who finds your journal. What do you think will interest him or her? What is happening in your life now that you want future generations to know about? Do you want to include advice for future generations?