I live in a high COL area that is quickly gentrifying so my whole town is a goldmine of anti-mustachian stories.
I moved into my town in the metrowest Boston area in 1999. This town is convenient to the interstate, had decent schools in the top third of the state, but wasn't one of the super quaint towns in MA with the well kept town center etc... so the home prices were more affordable. I considered it a high value town. It was primarily a commuter town full of working class people and white collar professionals. It has a large business center and a mall, but it is separated well from the residential area. I bought a house that was bigger than I needed, because I wanted to have children in a few years, probably "average" for the town at the time. 1960 construction, multilevel 1800 sqft, 4 bedrooms, 2 baths. Nothing fancy.
In the last 18 years, there have been a lot of improvements to the town. The town center, while still not great, is becoming nicer and more traditional looking. The schools have become nearly top tier. Since we have a large business community, we have dual tax rates which means very low property taxes compared to the surrounding towns. With home prices in the Boston area skyrocketing, this has brought an influx of wealthier families with young children to the town. So this has meant that there is a demand for housing, and home prices have more than doubled in that time. Great for me because I have a lot of equity now. But my town is starting the whole tear down, build McMansion process. The houses that people are building are sheer insanity IMO and look ridiculous in this neighborhood. I can't complain since their property taxes mean iPads in the school, great rec center services, paid trash pickup etc... However, my average house is now one of the "worst" ones in that it is small and not brand new.
The house across the street used to be a nice little ranch. Five years ago (which is about when this all started) it got torn down and a decent sized colonial got built. Then they decided a few years ago THAT wasn't big enough, so they added a huge addition. The house basically takes up the entire 0.5 acre lot. It's gigantic. They have three garages filled and 2-3 cars in the driveway at all times.