Out of all of the characters in the show, Fiona definitely uses facial displays the most. It is a motherly thing to so, even though she is not a mother. Fiona uses facial displays to convey messages to her siblings when they are up to no good in public. Whether they are trying to get some free groceries, or any essentials that they need, Fiona is able to give them the cue with her facial expressions. She is used as the distraction, so whenever she is sure that the person she is talking to is fully engaged in conversation with her, she will raise her eyebrows high. Once the kids see those eyebrows go up and her surprised face, they know it is go time. As the 'mother' of the Gallagher clan, it is understandable that she be the one to use facial display the most, whether it be for good or bad deeds.