I don’t think it’s a sin, but it’s not something to be proud of in my book. I consider it kind of impolite, though not hurtful or insulting and certainly don’t get angry at people if they swear.
I have a terrible habbit of swearing, yet I’m an intelligent, well-educated person. I ususally say a “bad” word when I’m overly excited or upset or even angry - but I would disagree that people swear mostly out of anger. It’s usually when I’m telling a funny story about my dog pooping (but instead the “s” word slips out). I’ll admit that sometimes I don’t even notice. I asked a friend to help me out. My friend said “oh - you just swore.” I was like - I did? What did I say and she said that I said “damnit.” Hmm… I wasn’t even considering that a swear until now so that I can mentally work that into my list of “bad” words.
I now try to stop myself and keep track of my progress. During Lent one year, I decided to say a Hail Mary every time I said a bad word. That helped b/c I took myself into a different state of mind. Of course, when you’re in a conversation, it’s kind of hard to stop and pray, but you can always keep a mental count and then wait for a quiet time to reflect and pray.