The beauty lies in the expressions....

Rating: 9/10 (18 August 2008)

... and the expressions take your breath away
That's what Oldboy is all about. The movie just keeps you hooked for the entire two hours (approx) and you are amazed at the originality of the script, action sequences, and acting.
Why to watch Oldboy: The movie is different from mainstream commercial Hollywood Its Korean and it scores over many Hollywood action flicks The originality of the script A very few loop-holes in the script Good action scenes
Why not to watch Oldboy: (Very difficult to cite reasons here) If you are a normal movie fan If you hate Korean people In case you hate watching movies while reading sub-titles
I'll say  go, watch it, and appreciate the skill displayed by the Korean director and actors in this action packed joy ride.