My fuel comes from Anacortes, not Houston. It may come as a shock, but Texas is not the center of the universe. I agree that Texas has a great tax scam going on crude, though. They tax every barrel of crude that goes through the state, so everybody east of the Rockies pays tribute to Texas, and that includes Europe. Europe relies on diesel much more heavily than the US, so we ship the diesel fractions to Europe and they ship us their gasoline. Not much of it ever makes it to the West Coast because the Suez and the Panama Canals are too small for the big tankers. Sending them around South America or Africa adds enough cost to make Atlantic supplies less competitive in the Pacific Rim trade.
Exxon shutting down their refinery in Houston will have little effect on the West Coast. Shell is just a US subsidiary of a much larger international company. I'm sure they can pick up the slack with storage and refineries in other countries. Frankly, shutting down Houston International Airport will have more effect on US air travel than a tighter supply of jet fuel. Airlines have had to divert thousand of flights to other cities.