I think some of the most anxiety-producing and frustrating things about traveling in a foreign country revolve around money.
Here in Oman, I’ve had ongoing problems finding ATMs that accept my card. This is because my bank keeps putting fraud holds on it, despite the fact that 1. I told them in advance about my travel dates and location and 2. I called during travel and told them again that it was not fraud. I had to tell them a third time last night to take the fraud hold off. Apparently, there is no solution for this problem and it might happen again (according to Duane, the sympathetic but only marginally helpful bank rep). Happily, the card is working for now. Also, it generally seems to work in stores (put not all stores accept cards at all).
Another issue is big bills. The ATM might give you a 50 rial note, which is equivalent to about $130 USD. Of course, like in America, no one wants to break a $100 bill. A lot of vendors refuse it, but I was able to get the cashier at the hypermarket to take it (I only had a 6 rial–$16–purchase), though he gave me kind of a look.
Even more, apparently Oman banks no longer accept checks from international banks. So, instead of being able to pay tuition with a cashier’s check, you have to wire the money, which incurs additional fees from your bank as well as the bank you are sending it to.
So, plan ahead if you want to visit Oman!