Then I pointed out that people, well, forget. That they can't possibly remember everything. I also knew that memories are quite unreliable and fictional.(I often fabricated memories about where I left my keys, which is often indistinguishable from true memories in my mind)
Of course, somebody suggest that we should build more reliable memories for longer lifespan, and another suggests that there will be so much to learn for a really long time so we won't get bored living a long life.