The third in the series of the Ten Commandments--"You shall not make wrongful use of the name of the LORD your God, for the LORD will not acquit anyone who misuses his name." (Exodus 20:7)
I really cringe when I hear someone use God's name in vain. I do not like movies that have the word GD used in them. Just hearing someone say "damn" is not like that to me. I occasionally even say that word myself, but when someone adds God's name to that expletive, suddenly it takes on new meaning. It makes me cringe, I suppose, because I was taught from the time that I was a child that saying that word was a major sin. It elevated cursing into a category equal to one using the F word (which I really do not want to hear either).
I suppose it has something to do with the idea of there being a separation between things which are considered holy and things which are ordinary. The Israelites' holiness code went to great lengths to define what was holy and what was not holy. Things that were considered to be holy were set apart and were treated in a respectful manner because of their holy nature. Holy things were protected and given special honor because they were considered to be holy. The Israelites built the Ark of the Covenant to carry holy items in as they went on journeys here and there. There was a list of specific things to be carried in the Ark of the Covenant which was itself so holy that no one could touch it. It had to be carried by 4 men who held long poles that ran through the bottom of it. There is a story in the Old Testament about a man who thought that the Ark was going to fall and he reached up to steady it and he fell dead. That story emphasized that the Ark was so holy that humans were not supposed to ever touch it.
So, things could be holy such as the Ark of the Covenant and its contents. Places could be holy also, such as where Moses stood when he encountered the Burning Bush and was told to take his shoes off because the place was "holy ground". Joshua had a similar encounter but this time it was with an angel and he was given the same command. Their shoes had to come off because the holiness of the place demanded that respect.
Setting apart God's name as holy is something that is still done in Jewish circles. Many Jewish people will not speak God's name and will not write it. They write G_d instead or use words such as Jehovah which was written using the same letters as in Yahweh but it was written by Germans for the German translations of the Bible so the Y became J and vowels were added since there are none in Hebrew. Judaism considers God's name to be as holy as an object one could hold and one is not to tread on the misuse of God's name in any way, setting it apart to be sacred.
I grew up in a family and church that also frowned on cursing and, of course, would never say GD or anything that may smack of it. I was not allowed to say what they called "by-words" which were words that sounded similar to curse words. I could not say "Gosh" because it sounds a lot like "God". I could not say "Gee" because it sounds similar to "Jesus". I could not say "Golly" because they said not to. I could not say "durn" because it sounded a lot like "damn". So, if I slipped and said one of those words, I was lectured or punished, depending on the mood of the one who heard me say it. One day I slipped up and said, "Gosh" and was reprimanded, and I said, "My gosh, I didn't say "Gosh durn" just "gosh"." I was severely punished for saying those words and for talking back.
I think the commandment forbids misuse of God's name because some things in life should be considered to be sacred, set apart, holy. Some things should not be ordinary. Some things should be valued or cherished. There are things in life that are special---days, such as birthdays and anniversaries and Sundays (that comes next in the line of commandments)--events, such as weddings, and baptisms, and funerals---places, such as the Grand Canyon and the Redwood Forest--buildings, such as churches and synagogues and historical ones. Setting things aside as special gives them special significance in life.
So, not saying God's name as a curse word recognizes that God is to be cherished and valued and honored and worshiped, and using God's name in the wrong way devalues our idea of what makes God holy. Our language does matter. When we use unacceptable language it has an effect on the kind of people we are perceived to be by others. We become less in the eyes of others because we have lowered ourselves to talk in such a way that some no longer respect us.