I've read multiple times over the years of people getting rid of their journals - sometimes throwing them away or other times doing it as a ritual. I have all of the journals I've ever written and can't imagine ever getting rid of them. I've been writing since I was a kid and have all of them.
I rarely go back and read anything but like having them all around. There are negative things in there at times, although I'm not a big "venter" in my journals. And there are lots of very personal things in there. But, I have never had anyone in my life that would read my journals (nor would I) and so I figure after I'm dead if someone chooses to read them it won't matter.
That's an interesting question.... What would people discover about you if they read your journals after you died?
In my case, people would discover I'm far more fragile than they ever imagined.