Sorry, but "fog" just isn't that scary.  The Mist was a 2-hour bore.  The last 15 minutes helped redeem the film a little bit - it totally wasn't a cop-out, but other than that it wasn't worth watching.  I'm not a big fan of sci-fi.  Creatures, aliens, dinosaur-looking things, whatever you want to call them, just don't scare me. Marcia Gay Harden was great, though.  Possibly worth a rental for the last 15 mins. alone, but not worth theater time.