[Merrill]

Dreams are maintenance. They are overnight batch processing after the realtime system is largely shut down. Your realtime conscious system then reboots from the now consolidated memory when you wake up.

You are a new and different person each morning.

[ASalazarMX]

This new and different person is practically indistinguishable from the old, though.

[Merrill]

It depends. For example, if you were drinking you may have been conscious of things the night before that you no longer remember the next morning.