Yuppie? Yuppy?

Whichever spelling prevails, this neighborhood is being inundated by Y-people. Call them yucky; call them yuckie. Not content with one Y-vehicle per person, the newcomers seem to have one super-large vehicle, one super-expensive sporty, roadster-type vehicle, and one very clean pickup, per person, and no gainful daily employment. And I didn't mention the untrained Y-for-yappy dogs trailing in their wake. At any hour of the day or night four or five of them (the incumbent tenants and some of their hangers-on) can be seen, and heard, milling around outdoors, each engaged in a cell-phone conversation. Who are these people? Some were observed to have Colorado plates upon arrival; perhaps they're trust-funders fleeing Boulder.