First time Monica screams her catch phrase, "I KNOW!!!!!"
The line in this episode "You have to stop the Q-Tip when there's resistance!" is Matthew Perry's favorite line of Chandler's.
This is the first time Ross is picked on for his hairstyle. This would become a running joke over the years.
Beginning this season, the view from Monica's windows has changed, especially from the living room. Instead of several buildings seen at a distance in buff brick with fire escapes, there is now only a single red brick wall, very close and with only a few windows visible.
Chandler recites lyrics from the song "Arthur's Theme (Best That You Can Do)" by Christopher Cross while commenting on Monica's new hairstyle. This song being the theme song of Arthur (1981), a film starring Dudley Moore, the person whose haircut Monica's is accidentally based on.