*
I tend to wake naturally around 05.00h; and if I sleep beyond this time then I recall that my dream narrative has usually finished, and the dream has gone into a more-or-less futile cycle of near repetitions.
Thus it seems like I have had 'enough' sleep - that whatever necessary work is being done in the brain during dreaming (REM) sleep has been completed; and after that point, things just go round and round until I awake.
I presume, here, that the dream at this late stage of sleep is a by-product of this primary brain work - because the primary quality of such 'futile cycle' dreams is their triviality, boringness, annoyingness - they feel like a pointless waste of time; therefore I guess they are just an epiphenomenon generated by some more fundamental process and purpose.
This is one reason why I want to get-up early, as soon as I awake - because sleeping later is just a matter of footling-around in these purposeless and repetitive cyclical dreams...
*
