The naive approach is to expect a Single Source of Truth for roads, address points, and the like, but this turns out not to be true. The road network and address points are usually done on a per-county basis, each with its own standards (and boundaries), and gods help you if you expect that a road in County A that proceeds to County B to "line up" if you import data from each county. Sometimes, parcels are separate. Oh, and they'll use different projections and fields and whatnot.
Meanwhile, the Department of Transportation for my state had its own road network: fewer fields, often skipping the tiny roads entirely, irregularly updated.
This doesn't even begin to cover how bad the plats of a new neighborhood are versus reality, how infrequently updated and checked data is, height and weight limits for stretches of bridge and so forth.