Continuity mistake: While Jack is talking to the police officer about the missing rent money, they are standing in front of the TV set and the front door is open. When it cuts back to Jack and the officer, over Jack's shoulder the front door is closed, but when the officer turns to leave the door is open again.
Trivia: In the episode where Janet asks Jack if she's a bad kisser, take a look at Janet when he kisses her. Jack unexpectedly slip Janet his tongue (which surprises the audience as well) and that throws Janet off and shocks her. Her surprised face is not acting, and was really surprised he did that. You'll also notice that when they part, she can't keep a straight face.