When Charlie is dancing with Vanessa and holding her from behind, his hand switches from her right breast to her left in between shots.
Charlie went to work, wearing a short-sleeved undershirt under his dress shirt, but he came back home, wearing a tank top undershirt under his dress shirt.
Charlie and Vanessa said they were going to steal their co-workers gin. However, the last scene shows him going to get some and referencing it as Johnny Blue, which is whiskey.