Retrospection is the act of thinking about the past — turning old days over in your mind, sometimes carefully, sometimes because you cannot help it. It is more formal than looking back, and a little more like a habit or a mental process than a single memory. You will find it in essays, psychology, and literature more than in the night market. Though actually, it is not the same as nostalgia. Nostalgia is a warm, often sad wanting to go back. Retrospection can be cool and exact, like going over a test, a fight, or a whole year to see what it meant. If you only need everyday English, looking back will almost always do.

回顧；追想