The brain makes obvious associations during wakefulness due to high noradrenaline, and distant connections during dream sleep due to increased acetylcholine and reduced noradrenaline.

“when you are awake and you're given some information you produce the most obvious links and obvious associations because you're very much blinkered and you have nor adrenaline on board but when you go into dream sleep the it's almost like the Google search when you're awake you go straight to page one and it's very related but do that same search when you're in the dream state and it you know you go straight to page you know 35 and it's an utterly bizarre page and you think hang on a second this got nothing to do with the search term when you read it you think well a squint my eyes kind of does it's very distant very non-obvious but that's a very smart connection that as a waking brain I never would have put together”