Yep! I'm the same age as her, and this is how we all speak to each other immediately upon earning/winning/receiving something incredible. It's from a place of love, but only works with friends and close acquaintances.
Sorry to hear that. Must be a cultural gap, but I can't find any justification to swear happily in random conversation - friend or not. Not to mention the one that conveys congratulations. If being close with someone is the explanation then, well, I really don't know what to say. There are so many words that could be used instead...
I feel the same as you, and I think it's worth thinking about. At the risk of sounding very "get off my lawn"-ish (I'm only early 30s!) I think it's related to the fact that our lives are now giant public soap operas being played out in social media for everyone to see. So the swearing at a person in congratulations is telling that how an envious external audience member would feel about their accomplishment, while the person you are swearing at takes absolutely no offense and is very complimented.
Swear words don't have to be negative. Language changes with each generation, words find new uses and connotations and intensities. I for one enjoy my generation's creative takes on conventional swear words!
