re: Are dreams the most unexplained human activity?

I read a study of a theory on memories and the most interesting facet was that when we recall a memory, we “take it out” of its memory bank and we “put it back in” when we are done thinking about it. This explains how some (not all) memories seem to change over time. Made sense to me anyway.

So maybe dreams are our brains’ way of de-fragmenting our memories.