1) There is that which is to us - that is, that which sure seems to be according to our understanding.
2) There is that which is - the ultimate reality of how things are.
3) There is that which we would change ourselves to become - that which we strive towards.
Idealists seek to make that which is to us (1) match that which we would change ourselves to become (3). Realists seek to make our goals (3) more closely match what seems “real” (1).
People who are both close-minded and see the world as nothing but an issue of perspective see (2) and (3) as being the same - that is, we only have the goal of unifying what we hope for with what really is.
I’m much more of an idealist than any of the above - I see (1), (2) and (3) as being totally separate, and I want them to all be unified into one. While changing (1) to match (3) is something I can try to do, I must not blind myself to the possibility that (3) is not in line with (2).
“There are more things, Horatio, than are dreampt of in your philosophy” - Shakespeare
Just as life propagates through the union of sexual opposites, ideas often propagate through the union of ideological opposites. It is the fascination with the “other” that often drives us to focus on that. It is, in my mind, one of the reasons why we tend to over-emphasize the divinity of Christ as opposed to his humanity (as I suspect Sam was pointing out in a comment), but I think that even more than that, it is also one of the reasons why we tend to emphasize gender distinctions instead of similarities, and thus create a sense of otherness that both fascinates and creates rivalries between the genders.
What motivates us? If it isn’t the union of (1) with (3), then we neither work on improving what we see nor how we see it - and if (2) doesn’t fall into there somehow, we might very well be doing it all under an illusion - which doesn’t bother me as long as I don’t know it - for habits can be unlearned, but real truths cannot - and nor would one want to.