A god that damns things isn't a part of my theology, but I consider "goddammit" a perfectly expressive expletive. Likewise, when I say "ohmygod", I very explicity don't mean _my_ G-d, I mean a generic, "Jesus H. Christ on a bicycle" sort of entity which has more to do with how English language cussing has developed historically than with invocation of the divine. I've been known to say, "oh my gods", too, despite only having one deity I consider _mine_. (When I say "oh gods", I am likely invoking a literary reference.)