Trivia: In "Four dreams" the alternative Allison who doesn't have children looks at some kids in a restaurant and gets a dreamy look on her face. The mother of the children she is admiring addresses her daughter as "Sofia". The "real" Allison's daughter Ariel is played by actress Sofia Vassilieva.
Trivia: The boy who portrays the young version of Arlo Slocombe, Enzo Rossi, is actually Patricia Arquette's (Allison's) son in real life. Arquette directed this episode herself and struggled to find a young actor who looked similar to Kevin Corrigan, who portrays the same character as an adult. Finally she realized her son looked quite similar and asked him to play the part.
Trivia: In several scenes, for instance when Allison is talking to Teddy's ghost in the kitchen or when they're eating, you can see the names "Harlow" and "Enzo" spelled out in magnetic letters on the fridge. These are the names of Patricia Arquette's (Allison's) children. You can see the names separate and together in some other episodes too, but rarely as clearly as in this one.