"Oh God" is a multi-use term, much like the word "fuck" serves multiple purposes.  And although I'm an atheist, I use the "Oh God" expression fairly frequently. "Oh God" was my reaction when I first heard this clip from Michele Bachmann explaining how God told her to marry Marcus Bachmann (even though they weren't in love or anything), and then went to law school and for her post-doctorate in tax law (even though she hates taxes) because her husband told her to, and the Bible says women must be submissive to their men! Of course, that's how she really feels. [...]