I love the word "recalcitrant." I also love saying "Don't hang that picture all cattywampus!"
"Balderdash" is fun.
"Rapscallion" and "Rastus" are always refreshing, as in, "Come here, you little rapscallion!" or "Hang on, Rastus, I'm getting there as fast as I can!"
One of my all time favorites is "pantywaist."
"Lackadaisical" is very descriptive - one of those words which sound exactly like what they mean.
"Hey nonny nonny" always catches people off guard. Another favorite is "pox" as in "A pox on you and all yore kin!"
"Cantankerous" isn't all that uncommon, but it sure does feel good to say.
"Serendipity" is a word that I can't say without smiling a wry little smile.
"Blithering idiot," "nimrod," and "pinhead" are often quite fitting.
"Poppycock!"
Now - this one is rude, but you have to admit it's a great word that should be used from time to time to keep it from dissappearing - "poontang."
Speaking of poontang, my grandmother always used to say "your under yonder" for that particular body part.
"Stop all your caterwauling!"
Here's one that's a real rarity - "larapin'" as in "Yum - that soup was really larapin!" I am not sure that's even a word, but it's definitely a coon ARSE word!