I have decided that from now on, whenever anyone says that, I will assume that whatever caused them to say that is their god.
Like, I'm playing Uncharted, and Drake and Sully just found an old rotted U-boat in the middle of the jungle. Sully's like "My God" and immediately I'm thinking "your god is a U-boat?" But hey, who am I to judge?
Or what about when Batman was like "An Amazon attack, a deadly bee weapon ... bees. My God." Now we know what Batman worships!
Next time you hear someone exclaim "Holy crap!" you know how a bee's digestive system works, too. Either that or a U-boat's.