Tipping
Angelika First off, there's the always puzzling topic of tipping. If you travel to the United States, you should always be carrying a bundle of one-dollar bills with you, as the bellhop at the hotel, the housekeeper, etc. will make sure that this bundle keeps shrinking as quickly as possible. But it is also an absolute sin not to give a tip. This is because, for example, the waiter or hairdresser earn such a low base salaries that they cannot survive without the additional tip. So, if the service is good, which is usually the case in America, you give at least a 15% tip, if the service is great, even 20%.
I tell you, in America they rely on the good old mental arithmetic when it comes to tipping. In California, there is a very simple trick, since the sales tax (i.e. what is called value-added tax in Germany) is 7.5%, you just have to double the sales tax and you have already calculated your 15% tip. But beware; since the tax in each US state is different (e.g. in Hawaii it is only 3%), you cannot blindly apply this trick everywhere. The sales tax gets always added to the purchase price when you're paying for something, which leads to the situation that you struggle to calculate the exact amount required and thus never have the right change ready, which means you walk around with a lot of small change that you can't get rid of for the reasons mentioned above.