I came across this verse recently: "Nor should there be any obscenity, foolish talk or course joking, which are out of place, but rather thanksgiving." (Ephesians 5:4) (I've put this in my Modesty in Actions post, too.) Wow, pretty direct! I also love the New Life Version: "Do not be guilty of telling bad stories and of foolish talk. These things are not for you to do. Instead, you are to give thanks for what God has done for you." I think we all do these not-great things at some point. However 'harmless' they may seem, God is against them.
And we also need to work on giving thanks. It's all too easy to tell a cool story and not give the due credit to God, for example. We need to publicly give thanks to Him for His work. (Psalm 22:22) What a challenge.