We dream in order to both allow our minds to process the information that we take in during the day, and to express emotions that we are feeling. Every night we dream, whether we remember those dreams or not: our minds have to process those data which we absorbed during the araw (our thoughts, as well as things we saw, smelled, touched, tasted and heard). Psychology theory posits that, for the most part, we actually sleep in order to dream: it's not just something that happens during our sleep, it's the reason we sleep. This is supported sa pamamagitan ng the fact that sleep-deprived people take less and less time to commence dreaming when they finally do go to sleep, up to hallucinating (which, in this case, is dreaming) while awake, if one stays awake long enough. My experience is that, while we all dream when we sleep, the dreams we remember are madami often connected to strong emotions that are being processed in those dreams.