I love the look of fog, but never breath the stuff anymore.  Very bad for your lungs.  Rule to follow is:

Never breath any air you can see!

I used to love the horror movies back in the day, usually foreign, that had lots of fog added for spooky effect.  I cared more for the movie’s atmosphere than the dialog and certainly like shadows and fog much more that buckets of blood, which by the way I think is the name of a horror movie.  The Fog was very eerie movie made in the 1980’s very well done.  I believe they did a remake years later which I have never bothered to see.  I have never seen a remake yet that I have remotely enjoyed.  They muck them up with so much needless gore that it’s just a waste of time to those not of a serial killer nature.