What's a notepad for?

I don’t want to moan too much but if there is one thing that bugs me it is reading a book that has been highliughted, underlined and annonated all over. Sometimes little words at the back of the book or inscriptions on the first page can add to the enjoyment of buying second hand books. But finding your eye constantly drawn to passages that someone else felt were important does undermine the enjoyment of the reading experience.