If it's your first time traveling to the US, you may find some things surprising. We've collected some guidance to help you!
Have friends or things you want to see around Los Angeles? You'll need to schedule lots of extra time to do that as California is very large and takes about half a day to drive from Mountain View to Los Angeles. Or wanting to head to San Francisco after the Summit? That's still over an hour drive (without traffic). Public transportation is not very good in California so if you are planning to head to Yosemite or Las Vegas you want to look into a rental car.
The price you see on an item is not what you will pay at checkout. Sales tax is added to your bill on checkout. States, counties, and cities can apply their own sales taxes so the percentage changes depending on where you are. Sales tax is 8.5% in San Francisco and 9% in Sunnyvale at time of writing.
Tipping is common in the United States where service staff are often paid minimum wage with the expectation that they are being tipped. A tip of 15% is the baseline, though many treat 20% as a baseline in places like the San Francisco Bay Area. If you tip less, that'll communicate that you were unhappy with the service. Tip more if you had a great experience.
Who do you tip? Almost anyone who provides you with a service: Cab drivers, waiters at restaurants, people who deliver food, valet parking attendants, hairdressers, and tour guides. It is also customary to tip a bartender a dollar for every drink, hotel staff a couple of dollars for each bag they help you carry or hold for you while you wait on your room to be ready. It's always nice to give hotel housekeeping a couple of dollars each day or at the end of your stay (leave it on your pillow with a thank you note), though this isn't as common, it is certainly appreciated.
Note: Sometimes restaurants will automatically add the tip to the bill, especially if you are in a party of six or more. There's no need to tip more in these cases.
You won't find many roundabouts in the United States (though more now than 10 years ago) instead you'll find tons of three and four-way intersections. In California, you're allowed to turn right on a red light if it's safe, unless there are signs saying otherwise (of course be sure to stop first, then turn right. : ))
Most gas (petrol) stations allow you to pay at the pump, but they ask you to enter a zip code when paying by credit card for security reasons. If you don't have a US credit card, you will need to go in and pre-pay. In some cases, you may be able to enter 99999 or prepend 0 to your post code (eg. if your post code is 7015, enter 07015).