Fractalize your mental patterns instead of reading as a whole (i.e., one single pattern, where the mood of the act is associated with the ego), that way you will be able to selectively associate yourself with a book instead of the act of reading. Most people stop reading when they are bored of reading, but by fractalizing your mental patterns you will be able to dissociate yourself from that particular book and move on to another book instead of stopping reading altogether.
"Be bored with a book, not with the act of reading"
—Nassim Nicholas Taleb, Antifragile
Taleb, Nicholas Nassim. (2015). Antifragile.