Well okay. You know how in Star Wars you see people living in places that look like ancient temples or adobe huts, but they have all this technology? That's one way ot sort of explain the feel of things. All the buildings are huge and old, maybe ivy covered, and like was said, trees are big and in some places their roots have begin to shift the foundations of some buildings. In Europe, people live in houses that are a couple hundred years old or more. Think of the narrow streets, that when orginally built, never expected the kind of traffic they see now. Newer architecture stands out, and newer things, like magic brass lamps that cast continual light, don't quite fit with the style of their surroundings. Everything is either cramped and small, or huge and cavernous. Old places serve new purposes. Some things just might be forgotten, like overgrown carvings on a building, obscured entrances to underground waterways, aqueducts still stand but are not used to transport water anymore.
People, by and large, would be complacent for the most part, and startled by change or something different suddenly appearing. Everything has a tradition behind it, even the smallest and most minor things. Many things would be well established, like businesses that handle common services, and educational facilities. Lots of "hallowed halls" and "august orders". Decadence would be heavy, and the richer citizens would be perhaps very decadent.
Magic will have made many things much easier for people, so the rich would have life very easy, the middle class would have it pretty good, and the poor would still do okay. I don't picture many beggars or hostels being found in the larger cities. In fact, I imagine that a large city would be a lot like a medieval version of a futuristic city, if that makes sense, where magic automates many things that fomerly required man or horse power. And the citizens are not amazed or impressed by any of it, because that's the way it has been, and they're used to it. Thousands of years of high magic would advance a society greatly, and they may have things that would seem very modern to us even, just powered by magic.
