When Rachel calls Mark while at the coffee house, she hangs up and places the phone on the counter next to the machine. A second later, the phone is placed on the machine.
Three of Joey's sisters were recast. However, the recast actresses playing them: Christina Ricci (Mary Therese), Drea de Matteo (Gina) and Marla Sokoloff (Dina), barely resemble each other at all.
Joey is incensed that Chandler fooled around with his sister, but in The One with Mrs. Bing (1995) (in which Ross kisses Chandler's mom), Joey tells Ross that "the code" states that a guy cannot kiss his friends' moms, but his friends' sisters are OK. However, Joey is thrilled when Chandler says he wants to date Mary Angela and was not just using Mary Angela to get over Janice, which would have left his sister brokenhearted.
When Ross is reading the note Chandler wrote, you can clearly see that the paper is blank.
When Mr. Kaplan Jr. comes into the room to tell Rachel to straighten the hangers in the closet, she's stirring her coffee and goes to place the stirring stick on the table and it falls to the floor. Rachel Jennifer Aniston) tries to catch it but lets it fall.
At the end, when Joey stand up to fight the man in the apartment upstairs and moves around the sofa, a cameraman is visible on the left side of screen.