SF and LA are pretty much at opposite ends of California.
The California-Oregon Border hits the coast at the 42 parallel, and the California Mexico Border starts at 32.5. SF's latitude is 37.8, making it only 55% of the way up the coast. Far from being on opposite sides of California, San Francisco is only a bit past the midpoint. The misconception that SF is at the opposite end of California is likely due to the fact that past San Francisco, Northern California is pretty sparcely populated (an Oregonian friend of mine once describe Northern California past the Bay as "not inhabited by humans").
There's a lot of background mess in our mental pictures of the world. We try and be accurate on important issues, but a whole lot of the less important stuff we pick up from the media, the movies, and random impressions. And once these impressions are in our mental pictures, they just don't go away - until we find a fact that causes us to say "huh", and reassess.
Here are three facts that have caused that "huh" in me, recently, and completely rearranged minor parts of my mental map. I'm sharing them here, because that experience is a valuable one.