If you haven't, I highly recommend A Pattern Language. It's full of fascinating insights into the ways functional design interacts with our lives (and perhaps moreso, how dysfunctional design impedes it).
Seconded. This is a really fascinating book for anyone who is interested in how space and environment affect us, or anyone who wants to build or remodel their own home/office/pub/any other human-used space. Whether or not you agree with any of the particular patterns (and there are hundreds), the authors' discussion of why they think each one is worth considering will make you think more deeply about the way buildings function and influence our behavior, and will prompt better, clearer ideas for how you want the spaces you live in to work for you.
It really is an incredible work. It changed the way I look at architecture, but also community and the importance of 'human scale' interaction.