The topic of love is a popular one for an analogy essay. The history of love as a concept is extensive, and thinking about love is common for both scholars and nonscholars alike. Love also lends itself to analogy fairly easily. For instance, love is like: a car ride, a roller-coaster, an adventure, a treasure hunt. You can write this either as a personal reflection or as a philosophical essay.
The film "Forrest Gump" popularized the line "Life is like a box of chocolates; you never know what you're going to get." Forrest was on to something. The subject of life is a good one for analogy. Much like love, life is a broad and complicated topic which can be explored in different ways: personal reflection, philosophical, literary or scientific, for instance. You have a wide range when choosing how best to compare life: anything from climbing a mountain to having a meal.
Losing someone or something can be an experience ranging from frustrating to entirely life-altering, depending on what is lost and how it is lost. Analogy essays on the topic of loss can range from losing one's keys to losing a loved one. In each case the analogy will differ depending on the significance of the thing you lost. Essays on this topic can treat one subject -- such as death -- or several in comparison.
Having a job is a near-universal experience; however, your experience with your job will vary a great deal depending on the kind of person you are and the type of job you have. Therefore, an analogy essay based on a job experience can reveal a lot about a particular job. The experience may be a positive one: "My job was like a fairy tale"; but it can also be a negative one: "My job was like rolling a ball up a mountain, only to watch it roll back down again."