A personal essay is like the human voice talking, its order the mind's natural flow, instead of a systematized outline of ideas. Though more wayward or informal than an article or treatise, somewhere it contains a point which is its real center, even if the point couldn't be expressed in fewer words than the essayist has employed. This emphasis upon mind speaking to mind is what makes essays less universal in their appeal than stories. The extraordinary flexibility of essays is what has enabled them to ride out rough weather and hybridize into forms to suit the times. A personal essay frequently is not autobiographical at all, but what it does keep in common with autobiography is that, though its tone and tumbling progression, it conveys the quality of the author's mind.
Nothing gets in the way.
Because essays are directly concerned with the mind and its idiosyncrasy, the very freedom the mind possesses is bestowed on this branch of literature that does honor to it, and the fascination of the mind is the fascination of the essay.