"You all know all about Eve... what can there be to know that you don't know...?"
That's what Addison says at the beginning of the movie, but he couldn't be more wrong. We don't know anything about Eve. Heck, looking at the DVD case or the thumbnail on Netflix, with Bette Davis' face front and center, you probably think she's Eve. However, Addison promises to tell us "All about Eve, in fact." Good job using the title, bro.
Pretty much everything about Eve is bad, and it takes a while for the characters to learn all about Eve along with us. Eve isn't the main character, but she's the catalyst that changes everyone's lives. The title hints that there's a lot more than meets the eye about this manipulative schemer.