What is mine, do not alter

When I let someone borrow something I wish for it not to be altered in some way shape or form. Like my poetry notebook which was returned to me with more poetry then I had originally had in there, and added on lines to my poetry. Them saying to me, “I completed the ones you didn’t finish.” makes it so I do not let them borrow anything ever again.

And when I let someone borrow a book to find they wrote in it and used a speed stick’s sticker to hold the cover on that’s when I get really annoyed. That sticker won’t ever come off of one of my favorite books. What am I to do with the person? leave them be? or confront them?