If I am reading a cookbook, tutorial, or reference to teach myself quickly so that I can accomplish something specific, I completely agree with you. Blog posts can teach something, of course, but when I choose to read a blog, I am hoping to experience a bit of the writer's personality and to be entertained in the process. Storytelling accomplishes both nicely. Also, when I read a blog post, I am not in a rush and don't want to feel like I should be.