It varies a little bit by neighborhood, but you get two problems at once imo:
1) specific nuisances by NIMBY boards – won't allow a new restaurant, a liquor license, a bar; favor projects approved by other rich people and their staid suburban-esque lives
2) specific nuisances that the city then learns from, internalizes, and turns into a policy norm – i.e. board X in Queens refuses to approve a bus lane/bike lane and threatens to sue, the city doesn't want to risk losing the right to build any bus/bike lines, so they give up ever trying to build bike/bus lanes because they want to avoid the conflict
That second category has a real insidious, subtle effect where the whole scope of projects attempted by the city gets weaker and lamer by the year because they anticipate losing out to community boards that (as bobtehpanda is saying) don't really represent anybody and tend to skew towards the people who can show up at their weekday afternoon meetings (by and large old people, retired people, people with more money, and you can go figure from there what that looks like demographically).