Channel Hop: In Britain the first season was shown on Viva very soon after its US debut - but after the midseason break it eventually started from the very beginning on MTV. Unfortunately MTV dropped it after season two, but fortunately for British fans Netflix came to the rescue (as they did for UK followers of Breaking Bad), and the series made its bow on the service from New Year's Day 2015.
Creator-Preferred Adaptation: "Preferred" might be the wrong word, but Sara Shepard, the author of the books, is a big fan of the TV series. In her authors notes, she mentions having regular dinners with Marlene King to discuss the show and she even dedicated "Deadly" to the four leads.
The Danza: Sara Shepard plays Miss Shepard, whose first name is probably Sara.
Confirmed in the opening of 'I'm A Good Girl, I Am'.
All four main girls are played by actresses who are between the ages of 20 and 25. Maya is the most egregious example as the character is 16 but the actress, Bianca Lawson, is 31. Bianca Lawson also appeared on Dawson's Creek in 2000 playing a 16 year old at age 20 making her an original Dawson Casting actress.
Averted with Alison. Sasha Pieterse was 14 when she was cast. She's now seventeen, but since three years have passed in-story, she's still the same age as Alison.
Actually inverted. She was 12 when she got the pilot.
Special mention goes to Troian Bellisario born in 1985 who is older than her teacher and her older brother Jason who were both born in 1986.
Directed by Cast Member: Chad Lowe (Byron, Aria's dad) directed "Touched By An 'A'-ngel," "Father Knows Best" (appropriately), "Kingdom of the Blind", "That Girl Is Poison," "Hot Water," "Into The Deep," "Who's in the Box?", "She's Come Undone," "Surfing the Aftershocks," "March of Crimes," ""Through a Glass, Darkly," "Game On, Charles" and "No Stone Unturned," "The Wrath of Kahn" and "Playtime"; Troian Bellisario made her directorial debut with "In the Eye Abides the Heart."
Fake American: Samara and Caleb's dad are played by Australians Claire Holt and Bernard Curry, Jenna by South African-born/Australian-raised Tammin Sursok, and Emily by Canadian Shay Mitchell. This is not the case for Alison because while Sasha Pieterse was born in South Africa, she has spent most of her life in the United States. And in-universe, Elliot Rollins is a Brit prtending to be American, played by actual Brit Huw Colliins.
Fake Brit: Because Alex Drake was adopted as a baby by an English family, she speaks with an English accent.
So many fans suspected Mona would die in the season 5 mid-season finale that they literally started to believe it was too obvious to happen, ending with them being shocked when it did actually happen. Then along came 'Welcome To The Dollhouse' which subverted that, by revealing Mona is actually alive.
"A"/Charles being a transwoman was considered one of the more out-there theories after it sprouted up during the sixth season. And then it happened. Weirdly, a lot of proponents of the theory failed to correctly guess which woman Charles would turn out to have become, even though Ce Ce, a character whose primary character trait is her resemblance to Alison, was the most obvious candidate.
Emily's stolen eggs and Alison's pregnancy are connected.
AD is Spencer's long lost twin sister, Alex Drake.
Killed By The Adaptation: Not only is Emily's dad renamed, he passes away offscreen. Also Maya, Wilden, Wren, Noel Kahn.
Lying Creator: Marlene King. She even outright admitted it when asked about why she stated Mona was dead when it was revealed to be false.
The Other Darrin: In the pilot Jessica DiLaurentis and Toby were respectively played by Anne Marie DeLuise and James Neate.