One tip to remember is that speaking Spanish will help you greatly. You'll be treated differently than if you speak English all the time, it'll help you assimilate, and you'll be able to communicate easier. If you're looking to learn Spanish, the two programmes I recommend are Synergy Spanish and Speak From Day 1.
Things are a bit different in Korea. Online banking is common which means that most banks close around 4pm. There are a few that are open 24 hours, like those at the airport. You can also do a lot through the ATM, like pay your utility bills (No rounding up either like they do in Peru. By skimming a couple cents off the whole population Peruvian utility companies have found an extra way to make money.). No guns either and the security guards are nice and usually wear white gloves, bow, and greet you as you enter the bank and upon leaving as well. As for cell phone? Koreans are addicted to them. Like Peru you might have to wait a while, but there are comfy chairs and you can use your cell phones while waiting. When your number finally pops up on the screen you get to sit down in front of a teller (who incidentally usually stands up, bows, and greets you as you come to their window).
I do miss the longer hours that Peruvian banks are open and the fact that they're open on Saturdays, but other than that, Korean banks are much better.