I found one probable answer in Aldous Huxley's essay, the doors of perception. It states-
In one of his studies eminent Cambridge philosopher, Dr. C.D. Broad states "The function of the brain and nervous system and sense organs is in the main eliminative and not productive. The function of the brain and nervous system is to protect us from being overwhelmed and confused by this mass of largely useless and irrelevant knowledge, by shutting out most of what we should otherwise perceive or remember at any moment, and leaving only that very small and special selection which is likely to be practically useful."Quite a revelation. Isn't it.
That might answer why the less conscious brain opens up more to imagination. But having said that, how do we channelise our thoughts and remember or note them, if not through a conscious mind? Well, there goes yet another confusion of a restless mind.