Not an immediate neighbour, but...
Just pushing the bike up the path to the front door, and a voice from the pavement says: "Fixed?" My mind being elsewhere, I could manage no reply better than: "Sorry?" He turns out to be a fellow fixie enthusiast from up the road, who (after asking) came up the path and gave the bike a good once-over, among other things pointing out that the headset was loose - I hadn't noticed, but he was absolutely right. I asked if he still rode fixed, and he said yes, but now he 'only' has a
Condor. (Love that 'only'!) Nice feller. Gave me his name & address, and said if I ever needed any tools I didn't have, there's a good chance he might be able to help out.