These four beautiful and talented actresses - Emma Watson, Mandy Moore, Penelope Cruz and Kristen Stewart (from top to bottom) are all included in this post because they are exemplifying Hollywood's version of a "Mona Lisa's Smile" (not the movie, da Vinci's painting). Most people don't realize that Leonardo's masterpiece shows a woman (classically described as Lisa del Giocondo) with a SUBTLE expression of contempt. So when actresses (or actors) try to emulate WHAT THEY BELIEVE Mona Lisa's expression is, they concentrate on their mouths. But don't let their beauty fool you - for if your girlfriend (or boyfriend, husband, wife, etc.) is ever wearing these smiles - she/he won't be sincere.