Anytime Jack declares a Beatles song to be one of the greatest works of art ever written, the people around him think he's just gotten incredibly cocky.
Right before, he searches for "John Paul George Ringo" and the first result is Pope John Paul II.
Rocky gives a heartfelt speech about how much being able to help Jack has meant to him just before the album release concert. Cue Rocky opening Jack's "door to stardom"...and the two discovering it's actually the fire escape.
Rocky is Mood Whiplash incarnate. Witness him stealing Ellie's crisps during her heartfelt talk with Jack at the train station.
Ellie: Not all the crisps!
Ed Sheeran has one of his own songs (Shape of You) as his ringtone.
Sheeran at one point challenges Jack to an impromptu songwriting challenge, with the two of them seeing who can write the best song in 10 minutes. Ed presents a simple, cheery song about penguins. Jack busts out "The Long And Winding Road." Ed very quickly admits defeat.
Every time Jack discovers another peripheral change to the timeline it's followed by a google search trying to see if it's really gone, complete with who/what is the actual first result. After getting confused looks asking for a Coke instead of a Pepsi, he types in Coke and gets directed to a page on Pablo Escobar.
Saying that he wishes that he hadn't given up smoking and could murder a cigarette, only to be asked what a cigarette is.
And finally, saying to Ellie that he feels like Harry Potter after he defeated Voldemort.
The sheer ignorance of the executives who shoot down Jack's Beatles-inspired ideas for his albums.
You know, I especially got a kick out of Sgt. Pepper's Lonely Hearts Club Band. Yeah, that's - It's okay to laugh, 'cause it's funny. It is. It's, uh, a lot of words, Jack. But ultimately, in the end, we just felt it was, uh, uh, too confusing, right? Too confusing. And, uh, The White Album has some diversity issues. That's a lot of white, Jack. And I know you were pretty enthusiastic about Abbey Road. I gotta say, it didn't have a lot going for it - if I can put it to you like that. Uh, it's just a road, with a bunch of people driving down the wrong side of the street.
A nice bit of Bathos during a heartwarming/Tear Jerker moment: Since John Lennon never became famous, he was never murdered in 1980 and is alive and well, and has lived a happy life at the age of 78. When Jack comments on this and asks a nonplussed John for a hug?
John Lennon, while hugging Jack: You need serious psychiatric help.
Jack's first attempt to play "Let It Be" for his parents and a family friend keeps getting interrupted, to Jack's increasing frustration.
