We have a lot of problems with Google Maps not knowing about odd addresses like 235B Whatever St. or 113-76 XYZ street. This is perhaps because its a new construction and the address isn't in the database yet.
Town names in the Hamptons are quite contentious. What the post office knows it as is not what the locals call it, and nothing like what the real estate agents call it (but they make up their own and they lie about the locations).
But primarily you need to parse native language and messy addresses. 2 Ave, First Street, Fifth Ave, Madison Ave (same as 5th), CPW (central park west)
This is where google wins.