I'm mostly reading that cussing may be a bad habit, but is not necessarily a sin unless it's God's name being used in vain, or directed against God or something holy, or another person. With another person, what about using it in a joke? I'm also from a military background, not to mention the guys. (Catholic and not) who I hang out with all the time. We joke around with each other to no end, and a big part of that is ragging on each other. Someone makes a comment about me, and I jokingly respond "f**k you very much..." or something like this. Everyone knows we're joking, so no feelings are hurt. Is a phrase such as this sinful, even though I'm not saying to break down my fellow man?
Also, with regard to the Lord's name in vain... I heard one priest give a talk/homily that seemed to agree with some of the previous posters. You shouldn't say "God" as an expression or whatever because when you say the name of God you invoke his presence without needing to... it's like calling him on the phone and hanging up. Another priest, on this website in fact, responded to the question of saying "Oh my God" as NOT being a sin, but rather a way to remind ourselves of our need for God, and invite him into our day, or a specific situation. He stated that often the name of Jesus is used irreverently, and certainly this is wrong, but phrases like "God help us," "God love you," or simply "God," when not used maliciously can be very appropriate. From personal experience, I even remember riding in a van with a very holy woman I'm friends with. The car in front of us on the highway stopped short, and we almost crashed. She cried "Jesus, Mary and Joseph" and thankfully we ended up okay. I asked her about it later and she said it was definitely a Prayer, not an expression. It seems in this context, even using the name Jesus is okay. It is a prayer after all. I mean, we say Jesus all the time... What about saying, "Jesus, please help me win this game..." or even "please help the Yankees win this game." Do we really need that? Isn't that using the name of Jesus "in vain?" Still, I don't think that's a sin. Jesus wants us to come to him with everything, praying constantly, even about the little things.
One final thought... God has many names, but actually, I'm not sure "God" is one of them. I guess we do use it as His name, I mean, I just did in the previous sentence. But the word god is really just the English word for a deity. The muslims worship a "god" whose name is "allah" (unless allah is merely the arabic word for god, I'm not sure).
I'm not being purposefully argumentative, I'm just raising questions that come up sometimes. I'm not claiming to be right on much of this either... call it playing devil's advocate, but if someone asked me why I DON'T make a habit of saying "My God..." I'm not sure I'd have the facts to tell them why I don't feel it's right. I was just raised that way.