One thing that I found so easy to do in Seoul was taking the underground. The system was very easy to follow – all you had to do is to purchase a card, load it with some small change and then start travelling.
Every stop has a number, so you can immediately see where you are on the corresponding map – and you can just figure out whether to go three stops north or two stops south. You don’t need to recognise the Korean station names (but most of them are in English anyway).
Interchanging is fairly easy too – just follow the colours and numbers!
The only thing that I found a bit frightening were all the emergency items stocked at each station – not just first aid kits, fresh water and fire extinguishers, but also gas masks!