Over the seasons of Friends, the characters and their quirks became more defined and even more lovable. Joey grew from a dumb lady's man into a sweet and lovable, but a little-slow-on-the-uptake good guy, who still had a fondness for the ladies. Chandler grew from the "transpondster" with a gay quality into a quirky husband who was still the funny man, but also would do anything for his wife. Ross perfected his ability to marry the wrong girl and to remain adamant about being on a break with Rachel, but was still a guy who was intelligent and would look out for his friends. Phoebe transformed from over-the-top homeless hippy to the quirky masseuse who realized she does want the conventional things in life. Rachel went from spoiled rich girl to successful career woman and loving mom, all without losing her edge.

What about Monica? Well Monica was able to live her dream of being a chef, a wife, and eventually a mom, but she never lost that one quirk that made her who she was: her obsessive compulsion towards cleanliness and control.

The fact that Monica was a neat freak was perfectly played in the episode titled "The One with the Secret Closet" in season 8. Chandler, now Monica's husband, realizes that there is a door in their apartment that he has never seen open. He asks Monica about it and she tries to dissuade him by telling him the closet is filled with "feminine stuff." Chandler becomes obsessed with the closet and at one point even wonders if Richard, Monica's ex-boyfriend, is in there.

Monica walks into the apartment as Chandler finally gets the door open (by taking it off its hinges with his wife's tools) and reveals a chaotic mess. Monica's secret messy side is revealed, making Chandler love her even more. Staying true to the Monica that we have grown to love, when Chandler asks if he can now put his stuff in there, Monica says no, because she is afraid he will mess it up. Even in her messiness, Monica still finds order. Classic!