A lot of spooky stuff went down at Central Perk without fans necessarily realizing it. There was the time an extra took a sip of coffee and proceeded to... chew it? There was another time when a tray that should've otherwise been filled with something like muffins or cookies was filled with a single potato. To make things even more suspect, the gang's usual table often had a reserved sign on it, and no one really addressed it.

Did anyone ever wonder how everyone always had so much free time on their hands? Besides Phoebe (who was a masseuse) and Joey (who was an actor), the others had full-time jobs. How did they have so much time to kick back at Central Perk and in their apartments? This weirdness was even called out once, when the gang was questioning why their bosses didn't like them and Joey responded, "Maybe it's because you're all hanging around here at 11:30 on a Wednesday." Must be nice.

Although Chandler's mysterious "transponster" job was the brunt of jokes throughout the series, did anyone ever stop to think about how much money this job was actually allowing him to make? How did Chandler afford taking care of Joey (like fronting the bill for his acting lessons) for so long? And how was he able to just drop his savings on his and Monica's wedding?

With 10 seasons and 236 episodes, Friends was bound to have some continuity issues every now and then. There was the time Sandy the nanny mysteriously went from having a blue puppet in his left hand (and a yellow in his right) to the opposite in a matter of seconds. Another issue came when Chandler and Joey moved their foosball table into Monica's apartment even after they broke it open to free the baby chicks. And can anyone explain why Ross was eating ice cream with Elizabeth even though he hated ice cream for being too cold? Or why Chandler said he'd buy a gym membership if he won money in Vegas, even though he and Ross already talked about having one?

No one on Friends seemed to know what their age was. In Season 7, Rachel's 30th birthday is honored through flashbacks of everyone else celebrating their 30th. This includes Joey, even though in Season 1 it was established that he was the youngest member of the group. So how did he turn 30 before Rachel? And she wasn't the only one who was confused about age. Ross was mysteriously the same age, 29, in multiple seasons of the show.

Rachel's name was spelled Rachel Green in the credits, but her last name was spelled otherwise as Rachel Greene all over the show. Rachel Greene was seen in places like her work office, on Emma's birthday cake box, and on Ross' wedding invitation.

In Season 4, Joey decorates his apartment for Ross' birthday with hanging paper cutouts and balloons. But they aren't just any balloons. If looked at closely, it's obvious that the "balloons" Joey hangs up are actually blown up condoms. Count on Joe to keep it classy.

For some reason, Rachel just keeps meeting Chandler for the first time. Rachel is seen meeting Chandler in a flashback scene when they both spend Thanksgiving at the Gellar's house. But there's also the time she met him when visiting Ross at college with Monica. They also still don't recognize each other when Chandler hits on her or in the first episode, when Rachel storms into Central Perk after running out on her wedding.

Although they were discrete, Friends suffered from a few unintentional wardrobe mishaps. For example, Chandler was supposed to be wearing nothing but a thong at a fancy restaurant in Season 2. But when he walks out using a door to block himself, viewers can quickly see he's actually wearing boxers.

On numerous occasions, the actors' body doubles were seen in plain sight, even if for a frame or two. Perhaps the two most obvious times were both in Season 8, once with Rachel's double and another with Monica's.

Clearly, these characters are confused about their age and apparently about their actual birthdays too. In Season 4, Ross tells Gunther he has a December birthday, but, in Season 9, his birthday magically changed to October 18. Rachel also told Gunther that her birthday was May 5, but, in Season 7, she tells a cop she's an Aquarius (someone who has a birthday in January or February).

A few actors on Friends sneakily appeared as more than one character throughout the course of the show. Before making her debut as Joey's agent Estelle in Season 2, actor June Gable also played a nurse during Ben's birth in Season 1. Phoebe's long lost brother Frank may have emerged in Season 3, but he actually appeared as a stranger outside Central Perk in Season 2. He accidentally dropped a condom in Phoebe's guitar case while she was performing in the street.

There's an entire Season 6 episode "The One Where Chandler Can't Cry" dedicated to Chandler's emotional emptiness, created as a product of his tough childhood. For the whole episode, the crew tries to get him to cry until he finally breaks. But Chandler can actually cry, like in Season 3, when Phoebe recounted the time she made Chandler "cry like a baby." Also like in Season 4, when he cried after Ross asked him to be his best man and when getting over his breakup from Kathy.

Monica's apartment, where most of the sitcom took place, was one mind-bending spot. Friends die-hards know that, throughout the series, the apartment number somehow changed from 4 to 5 to 20. Monica's kitchen window view changed too. First, it was covered by linens with not much of a view at all. Later, it looked out to a brick wall then to an outside view then back to the brick wall again. Lastly, in Season 10, Rachel was able to find an old apartment key that unlocked the door and led to the iconic head-through-the-door scene. However, this took place after the locks were changed in Season 8, so the key shouldn't have worked.

We never thought to ask questions about these things at the time because we were too busy enjoying the fun of the show. But, next time you re-watch, see if you can catch all of these things and more. It'll make watching the show even better.