Q. Regarding the placement of a comma after “of course,” I’d always treated “of course” used emphatically differently from “of course” used as an aside. With the emergence of better grammar checkers being utilized with an assumption of accuracy, I now see more of this: “Can I come over?” “Of course, you can.” Is this actually correct? I’ve been unsuccessful in finding a conclusive answer. Some sources say you always put a comma after “of course.” Others say it’s up to the author. Since it seems that the placement of a comma can change the meaning, I’d hoped for something a bit more definitive than “You do you, boo.”
A. The presence or absence of a comma after “of course” can make a difference, and any source (including your grammar checker) that suggests “of course” always needs to be followed by a comma is wrong. Though a comma can usually follow an introductory adverbial phrase like “of course,” such a comma is also usually optional (see CMOS 6.31). Of course, setting off a phrase like “of course” will emphasize the phrase itself. But to shift the emphasis to include the words that follow, you should omit the comma. (Of course you should.)