16 'Friends' plot holes and inconsistencies that still bother the show's true fans

Given that Monica's building doesn't have just one or two apartments per floor, it makes little sense for her rent-controlled sixth-floor walk-up to be apartment No. five.

It appears that the production crew noticed the same thing, because her apartment becomes No. 20 sometime during the first season.

Chandler and Joey's apartment also changes from four to 19.

Ross is comfortably employed, Chandler makes a lot of money, and Monica's apartment is rent-controlled because the lease is in her grandmother's name. But the show never explains how Phoebe is able to live on her own in Greenwich Village, a rather central and expensive area in Manhattan.

Phoebe is a masseuse, but she bounces between working at different parlors and massaging her own clients at home as a freelancer. She's even unemployed a few times after getting fired or getting her license suspended.

An episode on season two, "The One With Five Steaks and an Eggplant," specifically focuses on Phoebe, Joey, and Rachel's struggles with making less money than the other three.

The season three finale features a climactic storyline about Phoebe finding out that her birth mom is still alive.

Phoebe struggles with accepting her mom, whom she had never met or even knew existed, for a few season four episodes — but ultimately seems very excited that she finally has a real family member to rely on.

But after all that emotional buildup, Phoebe's mom disappears from the show after season four, episode 11, "The One With Phoebe's Uterus."

She's mentioned when she sends Phoebe a fur coat on season five, episode six, "The One with the Yeti" — but she's literally never mentioned again. She's not mentioned when Phoebe gets engaged, nor is it explained why she didn't show up at her daughter's wedding. (Phoebe does mention Lily, the adoptive mother who raised her, though. Interesting.)

Again, Phoebe meets her birth father after an emotional build-up. She had tried to work up the courage to meet him in earlier seasons, but ends up running into him at her grandmother's funeral on season five, episode 13, "The One with Joey's Bag."

After a sweet moment between them, it seems like they'll be able to build a relationship. But he doesn't show up again, and Phoebe never even mentions him.

The chick and the duck play a major role as Chandler and Joey's beloved pets in earlier seasons. They slowly disappear from the show and make their final appearance on season six, episode 20, "The One With Mac and C.H.E.E.S.E."

The birds aren't seen again, but the duck is mentioned when it eats Rachel's face cream and gets sick on season seven, episode two, "The One with Rachel's Book." (OK, we're all thinking it now: Did Rachel's face cream kill the duck?)

Given how much Chandler and Joey loved them, it's a little strange that no one mentions it when the birds die — which is only revealed on the series finale, "The Last One." (Joey apparently believes they were sent to a farm that doesn't allow visitors.)

On season four, episode five, "The One with Joey's New Girlfriend," Ross begins to tell Gunther that his birthday is in December.

But on season nine, episode two, "The One Where Emma Cries," he tells Joey his birthday is October 18 while filling out forms at the hospital.

Plus, if you want to get super petty about it, Ross implies on yet another episode that his birthday is in March. On season one, episode four, "The One with George Stephanopoulos," Chandler and Joey give him a ticket to a hockey game on October 20, telling him it's a birthday present — but Ross says, "Funny, my birthday was seven months ago."

Again on season four, episode five, "The One with Joey's New Girlfriend," Rachel tells Gunther that her birthday is May 5.

But on season seven, episode 22, "The One with Chandler's Dad," Rachel gets pulled over. The cop, looking at her license, says, "You're an Aquarius, huh?" — which would mean she was born in late January or early February.

Given that nearly every season features a Thanksgiving episode (except season two) and a Christmas episode (except season 10), the show implies that each season tracks one year in the friends' lives.

Ross, then, seems to age more slowly than your average man. On season three, episode 13, "The One Where Monica and Richard Are Just Friends," he tells Chandler he's 29 years old. On season four, episode nine, "The One Where They're Going to Party," all three of the guys say they're 29.

Then again, on season five, episode four, "The One Where Phoebe Hates PBS," Ross says he's about to be divorced for the second time before he turns 30 — which would make him 29.

Monica says she's 26 years old on season one, episode 22, "The One with the Ick Factor." Somehow, she only ages four years in seven seasons.

The season seven episode "The One Where They All Turn Thirty" features flashbacks for all the characters but focuses on Rachel's 30th birthday in the present. Monica and Rachel are the same age, since they graduated high school together, so we know Monica turned 30 that same year.

Though it's never clarified, Phoebe is presumably the eldest of the group. Ross and Chandler are the same age since they were roommates throughout college. We also know they're one year older than Monica and Rachel, since Ross mentions that he was a freshman in college when Rachel was a senior.

That would make Joey the youngest. He says he's 25 years old on season one, episode 23, "The One with the Birth" — after Monica already said she's 26.

But on the season seven premiere, "The One with Monica's Thunder," it's revealed that Joey has already turned 31, multiple episodes before Rachel turns 30 (who's the same age as Monica).

Rachel takes a pregnancy test on season eight, episode one, "The One After I Do," at Monica and Chandler's wedding.

We know from a previous episode on season seven that their wedding date is May 15. Plus, Rachel would've already been about one month pregnant, given that Ross reveals on episode three ("The One Where Rachel Tells...") that he and Rachel slept together "about a month ago."

Rachel is pregnant for nearly the entirety of season eight — which, as previously established, is equal to about one year of time in the "Friends" universe.

Season eight, episode nine, "The One With the Rumor," is a Thanksgiving episode. Rachel should be about seven months pregnant, but she isn't showing at all.

Finally, on season eight, episode 22, "The One Where Rachel Is Late," she goes into labor. She also tells Ross that it's "100 degrees outside," which signals that it's summertime in New York City. But she should have given birth around January.

Ross mentions his young son, Ben, tons of times throughout his ill-fated relationship with Emily. He cites Ben as the reason why he can't move to England with her, both before and after their wedding.

Curiously, however, Ben doesn't appear at Ross and Emily's wedding. Actually, his name doesn't come up at all, at any point, on the two-part season four finale in England.

Joey has seven (seven!) sisters that live close by, but they only show up in one episode. All seven sisters come to Joey's birthday party on season three, episode 11, "The One Where Chandler Can't Remember Which Sister."

The only other time that any of them show up is on season eight, episode 10, "The One With Monica's Boots." Joey's sister, Dina, comes to tell him that she's pregnant, which results in Joey promising that he's going to be there for the baby. Dina and her baby are never mentioned again.

We know from multiple flashback episodes that Rachel and Chandler have met many times. They spent multiple Thanksgivings together at the Geller house, and even made out once at a college party, as seen on season 10, episode 11, "The One Where the Stripper Cries."

Season six, episode 14 is literally called "The One Where Chandler Can't Cry." The main storyline focuses on Chandler's difficult childhood and how it made him "dead inside."

But this seems like a weird premise for many "Friends" fans, since Chandler isn't exactly known as an unemotional guy. He cries twice during season four alone: episode 14, "The One with Joey's Dirty Day," and episode 22, "The One with the Worst Best Man Ever."

On season six, episode 18, "The One Where Ross Dates a Student," he chows down on some ice cream with his then-girlfriend Elizabeth.

But later on season seven, episode eight, "The One Where Chandler Doesn't Like Dogs," Ross reveals that he doesn't even like ice cream.

"It's too cold!" he exclaims. "It hurts my teeth."

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