Everyone has the phrase that makes their skin crawl. For some it's too dorky ("Catch ya on the flip side!"), too dated ("word to your mother"), or just plain overused ("OMG!"). My skin-crawler is arrogance.
If I've just finished telling a story, whether it be for conversation, humor, empathy or whatever, please please please do not respond with "I've got one better", "That's nothin', listen to this", or any derivative therein. Basically what you're saying to me is "I don't care about your story. It does not push my buttons. Now I, on the other hand, have a story that tops yours in every way. Be my captive audience while I share it with you, and by golly you'd better get your hugely animated reaction ready because I've already told you that this story is the end-all-be-all of verbal commentary so I know you'll agree!!!!!"
Just once I'd love to get a response like:
"I can't top that."
"That is the best story I've ever heard in my entire life and I will never hear one better."
"I'll comment now for the sake of continuing our conversation, but it won't be nearly as good as what you've just shared."
"Can I write that down?"
"I have one similar, but it's slightly worse."
Now those are some idioms I could grab on to.