Roger is correct -- California is a beautiful state, and it is impossible to sterotype the people of of any state, let alone the most populous state in the US.
I lived in California about 10 years of my life. California does have its own culture. I'm not saying it in a bad way, but Native Californians on average are a bit different. I don't know anyone from LA, but my experiences are from San Diego and the Santa Barbara/Santa Maria area. I have visted LA and San Francisco, but don't claim to know people there. My best friend is from San Jose, and he is much like my friends from San Diego and Santa Maria.
For the most part, I find them very friendly, but when you get to know them you'll start to notice a few things. Their political views are more liberal than I'm used to. They will vote for anyone if they believe they can make a difference, regardless of whether they have political experience (Ronald Reagan and Arnold are prime examples). They seem to be a little more adventurous. Examples: scuba diving, bungee jumping, older folks riding motorcycles, skinny-dipping, open marriages, etc. Some of the "hippie" lifestyle still lives in them. I'm not saying all of them, but a good portion of the ones I know.