The counterpart to reflection is imagination. This is where we produce unreality, in all its forms. We do it when we come up with ideas what to do this evening, when we are creative decorating our surroundings, when we're problem-solving, day-dreaming, story-telling, lying ... you may be professionally making up stories (because you work as a scriptwriter) or seeking for high-opportunity scenarios (because you're an entrepreneur); you may be a little fearful and imagine all sorts of weird things that may happen when you walk a dark path at night, with shadows floating along and creaking sounds that can be heard; you may be re-inventing yourself every so often or creatively play around with world history (or the history of your town or company) to inspire people to get to the next level with doing something really worthwhile. In all these cases, imagination is the activity that widens the space in which we think and feel (and ultimately, act) by supplementing reality with counterpart worlds out of unreality.
I call them counterparts, not enemies; imagination complements, not subverts reflection as an activity. We constantly do both, and have to, in order to live our lives successfully. But they must be in balance.
Again (as with reflection), 'imagination' is a term that has had many, and for the most part much more strict and narrow uses in philosophy. And just as before, the way in which I shall employ it is broader. I use it mostly in the sense in which we say of someone that "he has no imagination". We'd say that of someone who normally acts in a certain way, has certain habits and preferences which all indicate that this person is rather not creative, imaginative, spontaneous, and so on. Someone, on the other hand, who does have imagination would brim with ideas, make up stories, try out new ways of decorating their surroundings, and so on. In other words, such a person would regularly produce unreality (deliberately and usually with the result of improving their own lives and that of others).
Reflection and imagination are in constant interplay, a complicated dance of forward and backward. We need both for success in our lives, though we must keep clear of the extremes in both direction: an excess of imagination can be as damaging as shutting it off completely. Imagination, the producing of unreality, gives us a drive and provides us with energy; reflection, the constant re-alignment with reality, gives us a sense of direction; because imagination is something that goes on in your own mind, it's also reflection that keeps you interactive socially. (Or, to put the point differently, the reality we're talking about includes social reality just as well as physical reality, historical fact etc. — reflection keeps you close to reality under all those aspects. Thus, it cuts down all sorts of fantasies about the behavior and opinions of other people, fantasies that otherwise might well lead you astray.)
Now, all this is only a very vague sketch, obviously there are many details yet to be filled in. There is, however, a connection with ethics in this point which I wanted to mention already at this early stage. Ethics, the study of character and leading a good life, is a particularly important stakeholder in the philosophy of unreality, and one of the main points of contact is the interplay between imagination and reflection with all its consequences.
 I've discussed reflection in this sense already in other blog postings: one on the reflective stance, and in another one that looked deeper into how reflection neutralizes unreality by facilitating a critical aesthetic stance.