|Maybe this is your house.|
San Francisco County, managed by a board of supervisors, all 12 of which are Democrats, has County Clerk offices 9.2 miles or 15 minutes away from your house. Only 8.6% of all registered voters in San Francisco County are Republicans. Meeting 20 people at random in the street, on average, you will encounter only 1-2 Republicans.
Sacramento is the home of the California State government. The State Capital Building is 79 miles away or a little over an hour's drive if there's no traffic. The state government is managed by Democrat Jerry Brown and a super-majority of Democrats in both chambers of the legislature.
If you live in Oakland, every appointed government official, from top to bottom, has been appointed by a Democrat, save for a few possible holdouts from Governor Schwarzenegger's administration which ended in 2010 or from George W. Bush's administration which ended in 2008.
The congressional delegation from the state of California is made up of 39 Democrats and 14 Republicans. That's 73% Democrat. Both US senators from California are Democrats.
The White House is 2,814 miles away or about 40 driving hours by car. Starting in January of 2017, the fellow occupying that position will be a Republican.
That many Republicans in positions of power in my world and that close to me would make me lose my mind, too.