California's population gives a misleading representation of our density, though. If you only counted the population from Los Angeles to San Diego, that makes about 22 million. The Bay Area (San Francisco, Oakland, and San Jose) has another 7 million, and save for a few exceptions most of California is very sparse in population. There's a lot of nature too, which is why a lot of films with nature settings are done there.
Another interesting fact is that Americans are more frequently diagnosed with mental and psychological disorders than any other country. Around 21 million suffer from mood disorders, 40 million from anxiety, 6 million from panic disorder, 8 million from PTSD, 2.4 million from schizophrenia, and 2.2 million from OCD. Cases of ADHD and autism are more common as well. (Those statistics stack, by the way; some people can have more than one disorder.)