Lined with stores and surrounded by high-rises, 3rd Avenue is a very busy stretch. Since there's very little in the way of attractions and destinations here, it's got a true neighborhood feeling. Adding to this atmosphere is the general lack of chain stores or restaurants; while there were a few, the vast majority were locally owned restaurants, laundromats, and moving companies.
Though I've lived on a few major streets throughout the years, living on 1st Avenue seems like an entirely different beast. In many ways it seems more like an LA highway than a NY surface street. If it weren't for the crosswalks, you'd never find your way to the other side.