Do longer books sell better?

It depends on content. If the book is super boring than I'd rather it be short so I could get it over with quickly. I don't think a very long and boring book would sell well at all. I think content comes first. Personally I don't buy a book because of it's amount of pages. What do most people do first? Read the summary on the back, or flip to the number of pages? I know what I do, and it's not the pages. Maybe as a whole longer books might sell better but I think this is just a coincidence because a lot of long books just happen to turn out good. I highly doubt they were published just because they were long.