4. 'Killer Joe' (2012)
The titular dirty cop in William Friedkin's jet-black comedy-thriller flaunts a sadistic streak that was a new addition to the actor's repertoire. Pure evil decked out in a cowboy hat and sunglasses, Joe Cooper is classic McConaughey because once again, he's the self-assured master of ceremonies. But instead of drawing us in, the actor pushes us back, letting the audience observe from a distance his sly seduction of Juno Temple's curious naïf and his inhuman brutalizing of Gina Gershon's schemer, which leads to the actor's nerviest scene ever. You'll never view McConaughey (or chicken legs) the same way afterward.