So I just had lunch at a Korean restaurant with some of my coworkers, and sat across from a woman who remained a stranger throughout the entire lunch. There was no attempt to introduce her in English, broken English, or even Korean (and I've recently been studying Korean intros, so I would have at least recognized the phrases, even though I haven't mastered how to say them myself). I would have taken the initiative and introduced myself, but then I didn't want to overstep. Now by western standards and I would think by most standards not introducing somebody in a shared social situation is rude. What do you think? Is it because I'm quitting? Because they aren't confident about their English? Why? Is it a cultural thing to assume someone will be introduced in a social situation? Incidentally, I found out later the woman is a new teacher. 
It's weird. I mostly think of Koreans as a very polite people with a slightly different idea of manners than we have in the west, but there are number of occasions that have challenged the politeness notion and this was a prime example. Anybody have a similar experience?
I've experienced similar situations in the past. Earlier into my time here it would have bothered but not anymore. I think what we have here is a mix of different things. On one hand they are either not confident in their English or the new teacher isn't in hers. They could have been being polite towards her by not putting her in an awkward situation of having to speak English to a foreigner in front of her new colleagues. Also, I've found that 'unnecessary introductions" are often just not done here. They probably figure you don't need to know each other so what's the point. You're leaving soon and unless she's an English teacher there wouldn't be much interaction between you in the future. Factor in that both you and a new teacher fall pretty low on the totem pole and you have another reason behind their not bothering. You mention having studied Korean introductions recently, and that's great. But do your school people know that? If you're coming to the end of a year long contract and during most group meals you've sat their quietly eating without saying much, they may feel that you also prefer to avoid somewhat stressful, profitless interactions.
The general rule of thumb here is that if something is uncomfortable and can passably be ignored, it should be. I don't think it has as much to do with anti-foreigner feeling as it does with hierarchy and avoidance of "needless" interactions. I can see the same thing happening to you if you were a young Korean contract teacher or administrative minion.
