This is a great topic! I got a great nostalgic feeling as I remembered some of my fondest childhood lego memories. Everything from where and when I grew up, to the friends I had, all play a part in my cityscapes now...
I love lego trains and with trains come depots, cargo docks, workers, housing, municipal services and a multitude of intricate viginettes sculpting everyday life. I love modelling the everyday in new ways: Superman kisses Lois in a back alley, a couple of kids put antifreeze in an old jalopy, a dog stares up at a cat on a fire escape...
When I display my city I love to watch people's reactions. Everything from awe (friends, family) to disgust (brother-in-law) to wonder (every child who sees it). Their reactions, even the negative ones, fuel my desire to build. I am a lego narcissist, I suppose. I am by turns a great architect, a cool uncle, dad, and grandpa, and sometimes even an eccentric nut, but I created something. I inspired awe!
I live for the wistful look in the eyes of adult "children" who recognize pieces of their childhoods. As a teary-eyed friend once told me (with a police boat clutched in his trembling hands) "I thought I was the only adult fan of lego in the whole world."