When you get to the end of a book you bought on impulse and you don't have the next book in the series. I'm feeling restless, irritated, distant, and distracted as a result.
I made the mistake of "buying"a few book off Amazon for my kindle and not realizing it was a series. (this actually happened to me twice ). I ended up buying the next 2 books on the series but then I did the same thing and had no money to buy the books in the rest of another series!