Trivia: Another comic book reference: they both have signature colors. Mr Glass' color is purple (his clothes, the envelope he leaves on the windshield, interior of his house, etc.) while David's is green (all of the interior in his house, his raincoat, his suit on the train etc.).
Trivia: There is a theme of upside down being bad. The girl in the train stands on her head before the crash. The son is watching TV upside down. When Mr Glass falls down he falls on his back and sees the figure he is chasing upside down. When Bruce Willis breaks into the train wreck, the warning sign in the gates are upside down. Willis falls head first into the pool. The comic book given to Elijah is first viewed... you guessed it upside down! Not a mistake, but great directing.
Trivia: The end credits list Robin Wright Penn's full maiden name as "Audrey Inverso". In keeping with the theme of the movie, the name sounds like a comic book character's name. The name Inverso also is consistent with all the reflective and upside down shots in the movie. Finally, the name is reminiscent of the "two sides of the spectrum" that Bruce Willis and Samuel L. Jackson inhabit.