Why Roll Your Eyes?

My wife has always expressed to me when she is annoyed or bothered by a certain something or someone. She rolls her eyes and doesn't say anything. She even has made me aware of this while we were dating. Well one night when we were out getting a bite to eat at Las Palmas I was talking to her and just telling her my opinion about the election which she felt strongly about her candidate and I felt opposite about her candidate for president. She rolled her eyes when I made the comment and didnt really say much after the conversation. I was worried I might have said to much against her candidate for president. But it turns out that she never even heard me comment about him and she was annoyed because the food had not come out yet. I was woried because I thought I was the problem, or at least I thought I was what caused her to roll her eyes. It was the slow restaurant.