I'm a huge fan of Korean movies, in the last decade they've really stepped up on the quality. A Bittersweet Life, A Tale of Two Sisters, Sympathy for Mr Vengeance, 300 Pounds Beauty, My Boss My Hero, My Wife is a Gangster, The Chaser, I Saw the Devil, Musa, My Sassy Girl, and JSA are among my favourites.
As a general rule, Korean movies do tend to dip into tragedy (or melodrama depending on your cynicism) in the last act, even their comedys and romantice comedies punch you in the gut.
Imagination will often carry us to worlds that never were. But without it we go nowhere. - Carl Sagan