Yes, I understand. I disagree with scribbling in your own books because (I found) scribblers often forget and do it in the books I lend them. Also, I inherited books from my aunt, who was a heavy scribbler, and it annoys me. It has a factor of having a connection to her, which I appreciate... but I also find her scribblings distracting.

Plus "your own books" are never truly just your own. In the example from the author of TFA, they are his family's. I wouldn't have wanted my brother's or parent's scribblings in books from our family bookshelves!