My diaries only contain appointments and folks births, marriages and deaths. And I used to note our meals so I didn't have to think too hard. I found a calendar one day, while having a clear out and read out week's menu to DH and asked when he thought it was. . . .next /last week? No, 10 years ago! Lol!
We had also kept the letters in shoe boxes we wrote to each other for a couple of years before marriage when DH (then fiancé) worked away. We had a look at them one day while having a clear out. Well, talk about boring, "nearly missed bus, had sausages for tea, think I'm starting a cold"! Absolutely nothing that interested us let alone future generations-so out they went.
I do envy folks who have kept interesting diaries esp in interesting times/places but not us.