Mark Twain says he considered titling his autobiography 'The Autobiography of a Coward' or 'Confessions of a Life that was a Failure'. This in order to try to be honest as opposed to most autobiographies and blogs for that matter which instead make the person out to be basically perfect. Of course if a person says negative things about themselves, there is the question as to whether or not they even realize they're saying negative things. Although whether or not they do, it still makes for actually interesting writing, which is something you virtually never find in the blogosphere.
For that matter there is conversely the chance that some people are really the angels they make themselves out to be. Like me for example.