Fridge / Matchstick Men

Fridge Brilliance

• While I thought Alison Lohman had a good performance in Matchstick Men, her role as a 14 year old was Dawson Casting... but since her character wasn't who she said she was, who's to say she wasn't at least a little older than she claimed to be too? Actually, since her character would then be pretending to be someone younger than herself who doesn't exist, in a strange way, it would sort of be in-universe Dawson casting! - Mike K
  She explicitly says this when they meet at the end. Roy says she looks "grown up." She replies "I am a grown up." She was someone Frank knew and got involved with the con.
• When Roy asks Dr. Klein for advice on how to deal with Angela, he tells him that the key to dealing with kids is just to "be as honest and open with them as possible". It sounds pretty innocuous, until we learn that Angela and Dr. Klein are working together to con Roy out of all of his money. With this advice, Klein was subtly telling Roy not to withhold any secrets from Angela, since Frank's plan relied on Roy giving Angela access to his account.
• Roy giving Angela signature access to the safety deposit box may at first seem like he's holding the Idiot Ball — but she did just try to "prove" her honesty by pointing out she never stole the money hidden in his dog statue.