Since we're all quoting lines...
"My dad always said, 'Why buy the cow when you can get the milk for free?'"
"Hey rookie, did you just call my girlfriend a cow?"
"No, I think he called her a slut!"
Ghost isn't missing taste, it's just that he doesn't know how to appreciate crude witty humor. Apparently RvB isn't good enough for him.
EDIT: Why is it that the characters have progressed at an overly inflated rate? Donut never acted gayish in the first season, but now he's Ambiguously Gay. Same goes with Caboose. He was a little moronic in his first few episodes, and now he seems just plain stupid. And O'Malley was considered a dark and evil badass at the beginning, and now he's twisted and insane.