I’m trying to change the culture in New York City that’s hard enough!

Bloomberg frames “culture” as something a mayor can attempt to reshape—norms of behavior, expectations of government, and civic habits—while acknowledging how resistant a large, diverse city is to top‑down change. The line suggests a pragmatic, managerial view of leadership: even within one jurisdiction, altering entrenched practices is a major undertaking, so ambitions beyond that (or distractions from that mission) are implicitly unrealistic. It also carries a note of impatience with symbolic politics; the speaker emphasizes the difficulty of measurable, on-the-ground reform in New York City and positions that task as sufficiently demanding and consequential.