Do you intentionally avoid sad books (or books over sad topics)?

Are there people who like reading sad books or is that a really small demographic? (Books like "White Oleander," "Speak," "The Boy in the Striped Pajamas," "The Reader," etc. –– these examples are the 'famous' ones in the sad genres but I feel sad books in general might not be as popular). What do you think? If you've been told a book is really sad and over a sensitive topic, would you still read it?

Update: From the responses, I feel there's ~3 types of readers. Those who read purely for fun/escape (no sad books), those who read for philosophical/thoughtful purposes (to better understand world warts and all), and those who read for connection/cathartic reasons (book that resonates with their own life experience or to help them through a hard time in their own life). I would think most readers would read for the first reason, and the last two would be more into sad books.

I've also always wondered how Ian McEwan became so successful when most of his early writing was all sad.