If it's a good book, I feel disheartened that it's come to an end. If it's not a good book, then I'm glad when it's done and over with, and I make a mental note never to read it again.
If it's a book that I am really enjoying, than i'm alwasys sad when its over. But if it's a really tough book to get through than I feel somewhat accomplished.
I feel so happy and thrilled that i have achieved what i want. I usually choose my books carefully. Finishing a book means a new beginning of another one
i have a feeling of loss as if there's something I have missed, especially if it was a good book, more lengthy, or a series. I also feel a feeling of completeness, so I am sad that the series is over, but I would not like it if the author made another book just because it was a long series and people did not want it to end, but of course I would have to read the new book anyway.
Depends, after I finished One Flew Over The Cuckoo's Nest, one word entered my mind: "beautiful" because it was a well written book. On the other hand when I finished Desolation Angels(a must read!) I felt depressed.