Em dashes—if properly used—are really useful.

They help convey that I am so smart—and I think so fast—that I have to constantly interrupt myself.

But—and I think this is important—it’s really easy to overuse them.

Ah, so my constant interrupting myself is a sign of intelligence? That's great news.

But seriously, trying to express the spider web of thoughts in my head as a linear string of words is really difficult for me and that doesn't make me feel very smart.