I have two sorts of dreams. Some are vivid and detailed, often recurrent, and I can recall tiny details long after I wake up. The others are still detailed, but within seconds of waking they dissolve. The detail starts to flake away, until by a minute after I'm awake there's nothing left. Evanescent would be a good word for them. It's a mystery to me why my conscious mind can't hang on to some dreams but it can to others. I like dreaming. My dreams are about 80% pleasant, with the rest being bureaucratic tangles in a Kafkaesque kind of way. I wake myself up if I'm in one of those to shake it off so that I can start again. I find that a small cube of Green's mature cheddar, taken at bedtime, encourages dreaming.