When you have a TV show that lasts for many years and several seasons, chances are its characters are going to go through changes. In fact, if you compare what they were like from episode one to the finale, you'll barely recognise them.
While it makes sense for certain characters to experience such a big change due to what's going on in the plot (Walter White in Breaking Bad, Carol in The Walking Dead, Sansa Stark in Game of Thrones, even Sawyer in Lost), there are some characters whose personality transplants made far less sense.
Whether it's the writers playing to the strengths of the actor, a change of editorial direction or simply bad writing, it's weird to see how much these people changed:
1. Monica Geller (Friends)
All six of the Friends saw big character changes from season 1 to season 10. Some were more subtle, like Joey slowly becoming more and more stupid and more obsessed with food, or Phoebe going from loveable hippie to borderline psychopath.
While Ross lost his mind more and more with each episode and became a cartoon character, we'd argue that his sister had the biggest change from pilot to finale.
For the first few seasons, Monica was arguably the sensible one. Sure, she enjoyed things being clean and was somewhat "high maintenance", but she was fairly stoic and easy going. But as soon as she got together with Chandler at the end of season 4, she totally changed.
By the end of season 5, she had become a high-pitched squeaky mess who resembled nothing like the Monica we saw at the beginning. You could argue that it was because she finally found true love with Chandler and let her "real" self through, but we can't help thinking it was just Courteney Cox hamming it up to 11.
2. Randy Marsh (South Park)
When Randy first appeared on the show he was just Stan's boring dad. He was a geologist, he hardly said anything and when he did, it wasn't anything too outlandish.
Fast forward 20 years, and Randy is suddenly not only one of the main characters, but has become even more childish than the kids, got into countless fights, inflated his balls to the size of beanbags just so he could smoke marijuana in public, and was even revealed to be Lorde in disguise.
This has probably happened as creators Trey Parker and Matt Stone have aged to the point where they relate more to middle-aged Randy than the boys.
Considering that we've since found out that Randy used to be in a boyband in the 1980s and has always had a wild streak, we're not quite sure how he became a respected geologist by 1997, let alone has managed to keep his job all this time.
3. Alex Karev (Grey's Anatomy)
If you've only been a fan of Grey's over the past few years, you'd be forgiven for thinking that not only is Karev the main male character, but has always been one of the nicest and most respected fellows in the show.
But it wasn't always that way. Right at the start, Karev was essentially the bad guy at the hospital. There were little redeeming features about him, he was mean to everyone, and he was surely only going to last a couple of seasons.
While it can be said that the reason behind his early dickishness was due to his troubled upbringing, and various situations like his failed marriage and working with kids have contributed to his redemption, we'd argue there's only one thing that has helped make him a good guy: sticking around.
Alex is only one of a handful of characters who have stayed the full course of 13 seasons. By default, he's become one of the show's most popular characters. He couldn't stay a git forever. After Cristina left, he became Meredith's new BFF. Why? Because he's the only one left. Fans are now shipping the pair, which for anyone bingeing it from the start right now sounds beyond bonkers.
4. Andy Bernard (The Office US)
Ed Helms joined the cast of The Office in season 3 as Jim's new colleague after he transferred to another branch of Dunder Mifflin. Helms was only meant to be around for a few episodes, but the cast and crew loved him so much, they wanted him to stick around.
Trouble is, Andy was a total prick at the start. And not even a loveable prick like Michael, a fully formed one. He was downright rude, mean and even tried to muscle in on Dwight's position as Michael's number two.
How did did they fix it? They totally transformed his character over the space of one episode. After being forced to take anger management courses after punching a wall, he returned a completely different person. If anything, he soon became one of the nicest of the lot of them.
5. Summer Roberts (The OC)
Another case of "We like the actor, so let's keep them". Summer was only meant to be in a couple of episodes at the very beginning as one of Marissa's vacuous best friends, but everyone loved Rachel Bilson too much to lose her that easily.
When we first meet Summer, she couldn't be more of a Valley Girl if she tried. Full of "ew"'s and only caring about herself and impressing boys.
By the end of the entire series, she was one of the most level-headed characters of all of Orange County, was a liberal animal rights activist and was getting married to the geeky boy who was obsessed with her at the start.
That was quite a transformation for someone to go through in just four years. Sure, teenage years can be the most transformative of your whole life, but Summer's character alteration was another level.
6. Barney Stinson (How I Met Your Mother)
We'll be somewhat fair to Barney, here. Because at the end, he's still generally the same crazy Barney he is at the start. But... he's getting married! That fact alone shows just how much he changed from the beginning.
At the start, Barney was a one-dimensional character who only ever wanted to chat up girls with Ted and sleep with as many of them as humanly possible.
For most of the show's run, this was generally the status quo for the Barnacle. But, in the last couple of seasons, he suddenly found himself wanting to start a family and get hitched, pronto.
Whether it was Nora or Quinn or Robin, it seemed Barney wanted nothing more than to walk down the aisle. What gives, dude?
7. Ned Flanders (The Simpsons)
A character who changed so much that he has a whole TV Trope named after him. Ned was originally just a friendly neighbour to Homer's clan. If anything, he was a bit of a dick if you watch the pilot again.
He wasn't even all that devout. Yeah, he went to church, but so did Homer. Before you knew it, he became totally obsessed with being a good Christian to the point of becoming a cartoon character. Oh, wait.
Writers on the show have said in the past that Flanders' character was deliberately changed, in response to the increased influence of religion in politics at the time. Flanders became a symbolic way to mock Christianity, before the so-called "Flanderization" was scaled down for him to once again become a nice but dull and religious man.
