I usually dont get into reading slumps because of a bad book but rather a very good book because I get book hungover and then sometimes I just don't start anything for along time and when I realize it I'm in a slump. So, for me it was Mistborn. I was so crazy over it that I had a bad time. To go back I usually just go for a series I left waiting on the 1st or 2nd book. Or something small I know I will enjoy or a book from my favourite author