Reset Confirmations in Calibre
I have been deleting too many books by mistake, now a days. Past Jason might have been pretty sure about what he wanted, but I sure as heck am not. So I had to do a bit of spelunking to figure out how to get the delete book option to confirm first. All I needed to do was Preferences -> Behaviour -> Reset all disabled confirmation dialogs Et voilà, Calibre now asks me if I am sure about deleting my books :)