Get an opportunity to teach a group of students about writing essays and APA style papers, and you will discover how big there exists gap of knowledge between them. In fact, you will discover that not all your students are ok with the knowledge that is involved in writing essays. They are in a range of difference and they will give different and divergent responses yet these are people who are being taught by the same teacher.
The same will happen when you are reading the essays that they have written; especially those that are done in the famous APA style papers way of writing. What you will discover is that your writers will tend to conceptualize issues involving writing essays and APA style papers very differently and the same will apply to the way they write their essays and APA style papers.
Students will demonstrate different understanding and application of doing APA style papers yet there is only one guide for writing APA style papers that you have used in teaching your students. Then you would wonder what the causes of these gaps are. Your students will write totally different essays which will earn them very different marks yet you are very person who taught both the best and the poorest student.
This is because students make different approaches towards learning the writing of essays and the writing of APA style papers despite being taught by the same teacher. They will hence do APA style papers that are totally different from one another. To write good or even better essays in whichever style, you must use your language well, organize your work and remain focused in your writing. This way, you will produce very good essays.