My opinion is that dreams are messages and experiences from the subconscious part of our mind. The deeper part which acts on instinct, intuition and emotion. The part which embodies most, if not all, of the true essence of ourselves. Some people call it the psyche, the Mind, the higher self, even spirit. But the words all describe a more primal, basic, fundamental part of ourselves.
I trust that more than my waking, conscious mind because that deeper part of myself - the part that is happy just being - hasn't yet figured out how to tell me to shut the hell up and it's all nonsense, like the surface part of my mind - the part which is constantly pre-occupied with working out how to be.