Why Does Snowpiercer Repel Me?

Can someone set me straight on Snowpiercer? The upcoming Bong Joon-ho-directed movie about the dregs of humanity living on a single train that endlessly circles an Ice Age-ravaged world is getting rapturous early buzz, especially in places overseas where people have actually seen it. So why am I planning to avoid it?

Snowpiercer sounds to me like a flat-out stupid premise, and the trailers — like this one, from France —  look as dull as the film’s muted color palette. What’s wrong with me? Why don’t I want to see Chris “Captain America” Evans lead a band of filthy rebels in an all-out attempt to capture the… er, engine of a train?

 What’s so wonderful about this damn movie? What am I not seeing?