The essay is not simply recording the facts or the result of pure imagination. Posts you make in a history lesson filled with facts gathered from various references may seem like an essay. However, no matter how conscientious you are in rewriting all the facts, even with your own language, it is not writing an essay. The essay is also not an event or experience that you write in a language lesson, no matter how real, smart, touching, sequential, clear, detailed, and complete your writing it.
Maybe you've made hundreds of papers in the above form and collect all based on "theme". You may call it an essay, but it's also not an essay. So is the essay? The essay is a written expression of the opinions of the author.
An essay will be better if the writers can combine the facts with imagination, knowledge with feeling, without prioritizing one of them. The goal is always the same, namely to express opinions. Essays can indeed vary according to the quality, type, length, style, and subject. Essays also can form simple to very complex, but all of them will show you a personal opinion as the final analysis. This is the fundamental difference between writing an expository essay or a report. An essay is not just showing the facts or tell an experience, and he slipped the author's opinion on the facts and experience.
Of course, you should have an opinion before writing the essay. It's just that, you also have to understand exactly what is meant by that opinion, how to deliver it, and how to express the value it brings. Before getting opinions, you must first determine the subject who want to be taken as opinions must relate to a particular subject.