California basically IS the trend generator.
Sushi in the 60s
Yoga in the 70s
Bottled water in the 80s
Japanophile culture in the 90s
The smoking ban in the 90s.
California wine culture in the 90s.
The green/organic food movement of 2000s.
CA didn't originate it, but that state is always the first to start or grasp the trend.
Hippy culture, Skateboard culture, surfing culture, casual fashion culture, car culture and the breakdown of formal wear culture, modern day gay rights movement, pretty much all started in California and spread eastward if not the entire world. Although high fashion is still dominated my Milan/NY/Paris, casual fashion is dominated by california. Los Angeles is responsible for the breakdown of suits and hats of your grandfather's time and the emergence of casual wear/ one layered wear as work and everyday wear. The denim as everyday wear is a california trend, as well as premium denim (faded, low rise, bootcut etc.)
Architecturally, even Disneyland had a huge effect on how cities were built. Enclosed "city-tainment shopping centers" like Citywalk and Disneyland are in every city. The idea of a metropolis center-less city/suburb is an LA invention that's taken over the rest of the US. Culinarily, California cuisine (the idea of using locally/seasonally grown organic produce and meats centered around grilling) as well as New American cuisine asian/latin american/-influenced multicultural fusion cuisine had it's start in California, so pretty much the most important food movements of recent years have started in California except for molecular gastronomy which still has not caught on outside of Spain.
And then you have the whole internet phenomenon which really took hold in Silicon Valley as well as the "tech coast".
All in all, the state is the most influential when it comes to "lifestyle" trends.