Tension is an interesting quality - and architecture must have it. There should be elements of the inexplicable, the mysterious, and the poetic in something that is perfectly rational.
I remember, as a young architect, people always talked about I. M. Pei's concrete. He had a particular specification no one else knew.
I always tend to think, even in residential projects, about what a space is being asked to do - where is it located, what are the circumstances, where can I attack the problem, so to speak. How can you create a narrative for people moving through it? How can you convey its character?
There isn't any one material that's mine. It all depends on the context. For example, I did a house that had the most exquisite marble applications. That sounds ostentatious, but it wasn't, given the context. The color white I subscribe to extensively. I love thinking about color, but I often go with white.
I'm not so interested in technology for technology's sake. I don't need incredibly sophisticated climate-control systems. And I'm absolutely amazed at the time people spend exchanging messages; I don't have a lot of time left over for those things.
When you have rules to abide by, does that curtail you as a designer, or set you free? People think of classical architecture visually, but I think the brilliant part of it is actually spatial.