I’m always confused by punctuations marks with quotations. For instance, where do you place the period when the sentence ends with quotes? Does the period go inside the quotes or outside? I know the rules (inside), but it still bothers me and I couldn’t figure out why … until I found this (emphasis mine)!
When it comes to commas and periods, though, logic doesn’t enter into the equation, at least not in the United States. Universal American usage places commas and periods inside the quotation marks, regardless of logic.
I was doing it all wrong with logic! It’s like measuring distance in America. Obviously, one mile is 5,280 feet. And one foot is 12 inches! DUH.