Ask HN: What interesting things do you write in your journal?

Hi everyone, I'm 22 and only recently I started keeping a journal. I believe it's a great way to preserve my memories and improve my English. Apart from writing just about the daily happenings and thoughts, I've also started writing about the mistakes I made, the reasons behind some of my decisions, any good quote I came across etc. I believe that these will be very valuable when I read them some 20 years or so from now.

Many of you also keep journals, So my question is: what kind of interesting things do you write in your journal?

Thanks in advance!