Continuity mistake: When Will stops Grace, as they are about to have sex, they sit up in the bed, and he tells her he thinks they should wait. In the first shot Grace's black strap is falling off of her arm, yet in the next shot it's back up on her shoulder.
Continuity mistake: When Jack reveals to Will that he is too shy to ask out the sales assistant in the Banana Republic, Jack stands by a wooden shelf. Between shots the positions of his hands on the wooden pole keep changing, and which hand is holding it with also differs.
Continuity mistake: When Dr. Hershberg is crying after giving some bad news, he knocks a grey box off of the small equipment table which he is leaning on. Later during the scene the box suddenly jumps back up onto the table. Also, the other items on the table jump around and change position on their own accord a few times.
Continuity mistake: When Karen is talking to the security camera in the cell, before receiving the phone call from Stanley, the pieces of salami strewn all over the bed change and some pieces disappear, most noticeably one piece on the pillow.
Continuity mistake: In the opening scene with Will, Grace, Jack and Karen, as they open the wine and talk about what they would like to accomplish in life, the newspaper disappears from the table during the scene, then reappears in a later shot.