Adding on to the discussion I would like to say that the amount of time you were lucid and its importance can determine whether you recall it or not. For instance I can know I was lucid than lose lucidity and if it was for only a short amount of time it wont last in my memory. The ones that usually stay with me are the ones that I'm lucid for a decent amount of time or the ones I find important. If I find other things happening in my daily life that are more important it easily gets forgotten. If not written down that is.