There are studies, I think, about swearing out loud actually reducing the subjective feeling of pain or discomfort
There's also a correlation with the sounds of said swearwords. Which tent to be more sharp and concussive. That's why "Fuck that shit" feels better than "Damn this mess"
Oh there are studies on it, at least the only one that matters :p (Mythbusters e142)
I have started unironically saying idgaf in sentences. Often when "fuck this shit" would fit as well. But fts isn't really easy to pronounce, where idgaf is pronounceable.
Though I agree, it's also interesting to see reactions when people don't initially understand, then think through it and realize what it means.
possibly because it could be easily confused with 'fix this shit'?
Who knows, theres no real rhyme or reason to how lingo evolves, somethings get popular, other don't others go through popularity waves and other totally change meaning.
For example, the origin of the phrase 'pull yourself up by your bootstraps' is, in its original context, meant to denote something that is obviously impossible.
You cant pull your feet up so hard you'll float or fly. Its like the modern nonsense propulsion/infinite energy memes from 4chan or plugging a power strip into itself to power it
But, nowadays, it means basically 'do something difficult and unpleasant', wíth the implication that 'i did it, so can you, if you cant or dont, there must be something wrong with you'.
Almost the opposite of its original meaning.