The two main cast, Dylan O'Brien and Britt Robertson dated off-set.
The character Aubrey Miller mentions at the theater that cheesy romance is strictly for Nicholas Sparks books. Ironically, Britt Robertson, the actress portraying Aubrey would go on to star as Sophia Danko in The Longest Ride, an adaptation from a Nicholas Sparks novel.
At the beginning of the movie (Silly Boy song) Aubrey appears four times but you can barely notice her. You can recognize her by clothes and bag.
Aubrey at the parking lot scene says that she is afraid that she is not going to be strong enough to be on her own, but in real life Britt Robertson moved to LA with her grandmother and away from her family when she was just 14 years old. Two years later her grandma left and she started living on her own despite being only 16.
When Dave is in Aubrey's house for the first time as he goes up the stairs he pauses for a minute looking at a photo of Aubrey and her parents. Aubrey looks at the same exact picture towards the end of the film when she is getting ready to leave for school.