When I was doing DOL in the 8th grade last year, one of the sentences I corrected I did so by adding an em-dash(—)——and it fit in context as a clause divider quite right, mind you——but they were all like "...what?". Yet now that I'm in big ole highschool, the tell you specifically *to* use it...pffft. I knew what I was talking ’bout back then, damnit!!
If you actually say "Doh" out loud while sitting home alone chatting with your online friends. And you might feel kinda stupid because your actually speaking with yourself.