I gave up on shelves a long time ago. The implementation on the Nook 1st Edition made way more sense and I haven't used shelves since then.
The key feature that has been missing since the N1E is the ability to see "Unshelved Items". Now, whenever you view the list of books to add to a shelf it shows you everything you have which means you need to hunt an peck through your list to find what you want all while you have to remember if it's been added to a shelf at all.
Agreed with both Purple Ice & Rignes.
I've given up on shelves, even though I LOVE organizing things. But it's just too difficult now.