Millennial Overspeak is a new dialect. Not every single person in that age group uses it, of course, but it’s an easy (albeit cheap shot) reference for unnecessary glitz, so it’s become a hard-and-fast impression.
Phrases such as “I’m SO going to do that,” or describing something as “Unbelievably, spectacularly good” is overkill. And like everything served up too often, you actually LOSE impact. So the words you’re choosing to make something “bigger” or more “dramatic” usually just make whatever you’re talking about come across as pompous, overstated, or simply trying too hard. These are qualities that push the listener away, rather than bring him or her closer to you.
Let’s try to make our words count. “He was dead” doesn’t need an adverb or adjective. “He was SO dead” doesn’t make it more expressive; it just makes you sound like you have to expand everything in order to feel important. Eww.