What, again, you want to do is expand in your answer. This is the worst thing you can say if someone asks you your opinion or if they ask you a question about something. As an example, someone might say, -"Ronnie, are you from Canada?" -"Of course." "Well, excuse me for asking." You only are going to use "of course" if someone has asked you a very, very stupid question or a question that they already know the answer to. As an example, you could say, "Ronnie, you're from Canada. Do you have red hair?" And I'd say, "Of course I do. You can see it." So when you answer "of course", it does not mean the same as "yes". "Of course" is a very, very rude way to answer someone's question if they ask you something. So please be very careful of this.