I've used that expression. I'm also well over 18, I've pondered what it means to be cliche, and I've determined that I've got enough problems without worrying about that.
That being said, there are some common expressions that irritate me and are best not uttered around me by anyone who wants to avoid a lecture.
Anyone who says "I could care less," when they clearly mean to say, "I coudln't care less," will be soundly mocked.
"Military style" drives me batty. It's often used to describe things that are neither military nor meant to resemble military stuff, or only some things that happen to bear some superficial resemblance to military stuff, but not others. People who use that term reveal to me their ignorance about both the military and the items they're describing.