I may consider it an illusion, I've always thought of it as an unobtainable feat. Something we place there as a standard above our own as a goal to work towards, and then once we get there the perfection is raised of course, because nothing we have could ever be considered perfection, for example, if we said "Well it would be perfect if I could get to his/her house in 5 seconds." and you can only get there in 6, and then we found a way to get there in 5 seconds, it would be "Well if only I could get there in 4." Until eventually we'd come to a point where it would be impossible to achieve anything else without reality occurring before it occurs, such as "It should already be completed, that would make it perfect." Which would mean our reality would have occurred and ended without a second of interaction by us to complain or criticize it's imperfection, as long as there is perfection, there will always be imperfection. I think it's unobtainable, something to keep us in a state of envy and strive, something to keep us lamenting, but also something to drive us forward.