(Minorish spoilers for 2012, but trust me, it doesn't matter)
Do you love movies about the apocalypse? Sure, we all do. One of the most unpleasant aspects of being aware of your own mortality is dealing with the fact that the world actually DOESN'T revolve around you, and once you're gone the story of mankind will continue just fine. In apocalypse movies, not so! Sure, you're going to die, but take this lovely parting gift with you; everyone else and the world!
As much as I love seeing famous landmarks fall down, it's a sad fact of Hollywood movies that the better the special effects, the most emotionally dishonest the story is going to be. I don't go to an apocalypse movie to feel good about how mankind's plucky will to survive can withstand even supervolcanos and ash blocking out the sun for a million years - I go for the catharsis of oblivion!
2012 does has some wonderful action setpieces in the first hour, and does a nice job of ramping up the tension on their way there. I would not entirely disuade you from spending 10-12 dollars on it, as long as you follow my advice on how best to enjoy it:
1. Sneak a beer in
2. Watch the first hour, or however long it takes them to get to China
Third and most important step after the jump...
3. Once they get to China, leave the theater and imagine a scenario in which all the main characters die, consumed with the horror and ecstasy of baring witness to the end of the human race.
If you need a visual aid, here you go: