There you go. I think that's it. When some one says that they have had a very long dream; life long, then we should not believe them. There is so little we can remember. That's why we forget so easily after a short while after we wake up. That's why it would be impossible to have a long dream, but you can have the feeling of having a long dream, but not actual events.

That's why we wake ourselves up so many times at specific moments, and that is because we want to remember the dreams. We need to be close to them in time.

When someone mentions the details of a "long" dream, I am willing to bet that there is so much gap filling in it. Otherwise we would not be able to describe the dream well enough to make sense.

The next time you talk or write about your dreams avoid filling in the gaps, and see what happens.