You have been too long in Korea when... (alcohol)

... when you start turning your head away from the table when drinking alcohol with elders.
... when you hold up your glass with two hands when someone older wants to pour you more alcohol.

No kidding. That's the 'polite' behavior in Korea.
When drinking with elders and somebody wants to pour you alcohol (and you cannot pour alcohol for yourself. never.) you first hold up your glass with two hands (never one. that is disrespectful.) and the elder pours you a drink. Then you wait for the cheers (at least during the first round).
While drinking you hold your glass with two hands, turn your head away from the elders, and drink. When an elder sits at your right, you turn left. When you have two elders at both your sides you turn completely, or you 'hide' the drinking with your hands.
With friends you can use one hand, unless they are older, then at least in the beginning use two hands. But never pour alcohol for yourself on your own. Never.

On my first evening back home after Korea, I actually did it during dinner with my parents. I was so tired after the long flight that I wasn't thinking much and we were drinking wine... That was a little embarrassing, but caused lot's of laughter.

To see what I mean, watch the video from 2:46. You got it all shown there ^^~