If you are going to talk about Psychology, you have to talk about the Big Five. It is such an important topic, that if it were to be left unsaid, one would not grasp Psychology. So it seems very cliche that I would still choose to write about it; but yet, here I am.
I will remember the big five for reasons such as this: I am using it literally every day. I cannot help but evaluate myself and how I rate in every category. When I took the test, I scored the highest possible score for extraversion. It made me laugh, but it is the truth. I look at my second top score, which is agreeableness, and understand how I am able to relate to people so well. Constantly throughout the day, even though I would rather relax sometimes, I am evaluating people to see what personality characteristics are prevalent in them and which are not.
I hope to go into management someday. I intend to be a engineer after college, and I want to manage engineers. To do so effectively I have to understand who people are, down to their core, and understand where I can put that person so they will be the most productive. The Big Five is the simplest way of understanding who someone is. That is why I will remember it in 5, 10, and who knows, 45 years from now!