Generally speaking, there are two reasons I haven't read any given classic or popular recent book:
1. I suspect I'm not smart enough to understand it.
2. It seems much too boring to get through it, given my lack of interest in the subject.
Sometimes it's both reasons, but I will choose the one that I feel more strongly.
I even own some of these, but still haven't gotten brave enough to try them.
For this list, odd numbers are, "Sharky is too obtuse for this book,"
and even numbers are, "This book is too tedious for Sharky."
Please feel free to make it a trend! I am very curious about your lists.