Whenever I read a piece of writing that includes an em dash, I'm unsure wether to read it as an afterthought or added emphasis. Here's two examples I made:
The em dash being used as an afterthought:
"There was 130 of them—and, yes, I counted them all."
As added emphasis:
"I don't want you all showing up to my party—especially you."
So, which one would it be? Is the em dash used to show an afterthought or added emphasis—or both? (Pun intended.)