In the scene where Mel Gibson waxes his legs in his bathroom, he actually did wax his legs, and it did not hurt him nearly as much as it hurt him in the movie. He kept taunting all the women on-set, saying, "Come on, this doesn't hurt at all!"
In an early transition scene, there is an aerial shot of the camera panning over water and up into the Chicago skyline as the sun rises. This is the same footage used in the opening credits for the sitcom Family Matters (1989).
When Nick is in the lunchroom receiving feedback regarding his advice to the co-worker moving to Israel, the woman says "I don't think it was you got it, see you next Tuesday". See you next Tuesday is a euphemism for vagina. C.U.... It could be a complete coincidence, but as their conversation ends, Nick moves his head to reveal a portrait that resembles the female anatomy.
Nancy Meyers was hired to re-write the script (uncredited) before she was asked to direct it. She said " I got to say a lot about what I was going through in my life. There are speeches and nuances that were pretty much what was going on with me. I spent six months on it, and I didn't keep a lot of what was there."
One of two 2000's releases starring both Mel Gibson and Logan Lerman, with the second film being The Patriot (2000). In this film, Lerman plays Gibson character as a child, while in the war epic he played one of Gibson's sons.
When Nick decides to get music from his daughter's backpack, he finds Fiona Apple's "When the Pawn..." and Alanis Morissette's "Jagged Little Pill" before settling on Meredith Brooks's "Blurring the Edges" (commenting "She's hot"), leading to him dancing and singing along to the song "Bitch".
The trivia item below may give away important plot points.
The color of the main characters' wardrobe reflects their mood. Mel Gibson's character wears black and dark colors throughout most of the movie, while Helen Hunt's wears white and lighter colors. The opposing colors match their character's being at odds with each other. It isn't until later in the movie that both wear gray, singling their characters coming together.