I love finding notes and inscriptions inside books as well! I helped a store I worked at purchase used books, and it was honestly great whenever I found copies that had personalizations.

I notate books that mean a lot to me, like my copies of Marcus Aurelius. I've given a couple of those notated copies away over the years, hoping my thoughts help the people I've given them to in some small way. It's sharing a bit of myself, showing that what I'm giving isn't just a book recommendation, it's a piece of who I am.