The golden round shaped symbol that Kate (Marisa Tomei) is wearing in the scene when Cal (Steve Carell) hits on her actually refers to a married women in the Indian tradition, although she is single here.
The name plate on Emily Weaver (Julianne Moore)'s desk had a second line "Associate to the Vice President," not "Associate Vice President." This is undoubtedly a reference to Steve Carell's TV series "The Office," in which there was a running gag about Dwight Shrute having the title "Assistant to the Regional Manager," not "Assistant Regional Manager."
The cocktail that Jacob drinks and makes throughout the movie is an "Old Fashioned," considered by some historians to be the first American cocktail. The recipe usually included sugar and bitters muddled together, club soda and ice, rye whisky, and a large slice of orange peel.
When Jonah Bobo's character, Robbie, is deleting Jessica's number from his cellphone you can read that another contact in his phone is 'Joey K'. Joey King is the name of the actress playing Molly, his sister on screen.
Stars Steve Carrell, Julianne Moore and Emma Stone all went on to receive Oscar nominations at The 87th Annual Academy Awards - Steve Carrell for Foxcatcher (2014), Julianne Moore for Still Alice (2014) and Emma Stone for Birdman (2014). Moore won; Carrell and Stone lost.
Three out of four of the leading roles, Steve Carrell, Julianne Moore and Emma Stone were all up for Oscars in 2015. First time nominees Carrell in the lead actor category (Foxcatcher) and Stone in the supporting actress category (Birdman). However, only 4 time nominee, Moore, won the Oscar for leading actress in Still Alice. Gosling was also nominated at the 2006 Academy Awards for leading role in Half Nelson.
In the scene where Ryan Gosling and Steve Carell discuss getting "Mr. Miyagi'd", Gosling grabs Carell's nose and squeezes playfully, saying "Honk!" This is a reference to "The Karate Kid Part II" where Pat Morita honked the nose of Martin Kove instead of striking him.
The trivia items below may give away important plot points.
Marisa Tomei's character is revealed to be Robbie's English teacher when she first meets Cal at the bar, as she is wearing the same watch and bracelet seen when she writes on the blackboard earlier in the film.
In the film, Cal and Emily had Hannah when they were teenagers, but in real life, it's very realistic that Steve Carrell and Julianne Moore could be Emma Stone's parents since Carrell is 26 years older than Stone and Moore is almost 28 years older.
You never find out what Jacob "Ryan Gosling" does for a job throughout the movie. You see he has an incredibly lavish lifestyle but you never know what he does. The reason he can afford all that he has is through his father. Jacob says in the movie, while talking to Emma Stone's character, "He was very successful, in business. He got a lot of money and that's why I could afford all this."
Through out the whole movie everything is known about all the characters except for Hannah. All we know about her us that she graduated from law school. It isn't until she goes to the anniversary party of the Steve Carrell's and Julianne Moore's characters that all is revealed about her.