San Francisco and Orange County are both coastal California, but the day-to-day feel is genuinely different. Trading a dense, walkable city for a county built around distinct suburbs and beach towns is the biggest adjustment most SF transplants describe.
Pace and density
San Francisco is compact and transit-friendly. Orange County is spread out and car-dependent, even in its more walkable pockets like downtown Huntington Beach. Most people end up driving far more than they did in the city.
Cost of living
Housing costs shift, but not uniformly. Some OC areas run comparable to SF, others considerably less, depending on proximity to the coast and the specific city. It's worth comparing specific neighborhoods rather than assuming a blanket discount.
What SF transplants ask about most
Commute patterns, whether to go coastal or inland, and how good school districts compare to what they're used to researching in the city.