Why can't I remember my dream after waking up, but only an unforgettable fragment or picture?

Dreams are reactions or fragments of spirit, mind and thinking. Generally speaking, the memory of dreams is in the sleeping room. Once you wake up, your memory is only about 60%, and it may be about 30% after ten minutes. You don't need to record it deliberately. Unless the contents of some dreams often appear or leave a deep impression on you, such dreams can be carefully analyzed according to Freud's concept, which is the true reaction of your heart or the manifestation of your subconscious mind. In case of such dreams, you can put a pen and paper on the bedside or write it down quickly, and then seek the help of a psychological counselor for analysis.