This sentence was originally from Gu Xiang's "Western Paradise". The original text was "Those things that we thought we couldn't forget were forgotten by us in the process of our obsession." This sentence means that people are often immersed in the memories of the past in the process of pursuing a certain goal. These memories are often gradually forgotten with the passage of time. This phrase was often used in novels, movies, and other literary works to express the impact time and experience could have on people's memories.