I wish my great-grandparents had kept journals. Pretty sure the text would have been written in Czech, but invaluable nonetheless. All I have now are fading memories of Gramma (Grampa died a year after I was born), and believe it or not I was too shy to really talk to her much... not that she talked a whole lot to begin with.
But it would be interesting to have a window into their minds, especially during their transition from the old country.