In the book, Angela does not (and is never asked to) go on the road trip.
Cara Delevingne wasn't the only person considered for the role of Margo. Shailene Woodley was originally cast, but had to drop out due to clash of filming schedules with Insurgent. John Green said he would have chosen Emma Blackery, a fellow YouTuber, for the role, but he admitted the casting wasn't up to him.
Cara Delevingne's audition for the role of Margo was outstanding according to John Green (book author), "Cara Delevingne's audition blew everyone away (including me!) and she understands Margo profoundly. I am so excited!" Mr. Green tweets in mid-September.
When Margo and Q are dancing in the SunTrust Building, the background music is an instrumental version of the song, "Lady in Red" (by Chris de Burgh). In Q's dream sequence scene, Margo appears to him in a red dress.
Margo R.S's black notebook plays a big part in the book while in the movie it is shown as an easter egg at the end of the movie.
Ansel Elgort: , who portrayed Augustus Waters in The Fault in Our Stars (2014), also by John Green, as a gas station cashier. Elgort's character is named Gus, and funnily enough, the guy in the building that Margo and Q visit is named Gus as well.