Basically, I'm complaining about my brother not having heard of stuff.
Previously, he didn't think "grok" (understand) or "po-po" (slang for police) existed, simply because A—I was saying it, and B—he never heard it before I said it.
Currently he thinks the hyphen-word "head-space" (similar to "mind-set") didn't exist simply because he never heard it before.
Howzabout YOU fellow tropers? What words and phrases (that actually exist) have YOU heard of that you get annoyed that your siblings/friends complain of not having heard of before?