"The Game" - very immature and sophomoric book. I was given this book by an acquaintance who was also geeky like me. I was painfully shy of girls until grad school, and this book gave me much needed confidence to talk to the opposite gender. A lot of the content is garbage but this book was definitely a life changer.
"Hobbit" - Great story that got me into the LOTR. Shorter than LOTR and hence why I put that on this list. Also about being brave I suppose. I'm seeing a pattern here.
"Good Omens" - Not sure why but when I read this book, I was convinced it was the best book ever written (and I used to read a lot of books in youth). Just witty writing and the occult I suppose.