In the second season, Gary instantly calls out a psychic to be fake, claiming they're not real. James Roday Rodriguez is best known for his role in Psych (2006), playing Shawn Spencer, a fake psychic.
The shirts that Maggie wears in earlier episodes reflects her Chicago roots. In later episodes, she is seen wearing shirts from Boston area sports teams.
The production used Wendy Poole Park in Vancouver in season 2 but used CGI to change the name on the Park's engraved rock sign to "The Francois Lawson-Rodriguez Park." This is likely a reference to the real-life couple of James Roday Rodriguez and Maggie Lawson.
The TV show's creator, DJ Nash, based "A Million Little Things" off an encounter with his friend who he had not seen in a very long time by bumping into him on a walk and then heard that he had committed suicide a little time after making plans to go have dinner next week.
While only for a very brief stint of a few episodes, this is the second time David Giuntoli and Sam Anderson have worked together on the same series. The first being "Grimm" (2011), where David was once again a main character and in every episode, while Sam briefly featured as a one off character.