I think everyone has pretty much answered your questions but bottom line is if you want to spend time at the beach in California, come July-September and visit either LA, San Diego or Orange County. Laguna Beach would be good to see the California life style you are talking about.

Ziana;

You were amazed that the ocean water in California was so cold, too cold to swim in.

Easytraveler explained to you the geographical reason why the water is cold in the Pacific Ocean and why it is so warm in the Atlantic ocean.