In 2004 Greg Behrendt and Liz Tuccillo published He’s Just Not That Into You, a dating guide that became a film in 2009. The title came from a line in Sex and the City. One chapter is titled “He’s just not that into you if he’s not calling you.”
Behrendt wrote: “Calling when you say you’re going to is the very first brick in the house you are building of love and trust.”