Try what I did once. When the "clerk" asked me for my last name, I said "Sale". He had a hard time spelling that, and then asked for my first name and I said "Cash". After a few seconds of letting this puzzle sink into his pea brain, I said, "Just write down Cash Sale and don't ask me any more questions.
He had a difficult time comprehending that, but after some hesitation and herculean mental gymnastics on his part, I walked out with my merchandise.
I seldom purchase anything from RatSh!t because they can take a piece of wire 2" long and turn it into krap (tm). Sometimes they are the only place to buy some simple electronic part, but their stuff has been so bad, that I'll go to the local Rite-Aid, Walgreens or Walmart instead of buying from RatSh!t.
There *is* some pleasure though in saying "Just write down cash sale, ring it up and give me my stuff" to the stupid retard there.
About the only question they have answers to is "where's the door?"
Come on now, no need to be ignorant! RadioShack employees are people too, and I'm sure, like all companies, they aren't allowed to sock customers in the face when they are rude to them! Controlling this urge can often be confused with facial expressions appearing to be looks of confusion. I've worked retail before - I know this feeling! Usually the thoughts going through my mind included "this guy probably thinks he's funny" and "wow, I think I'll take as long as possible to do this, pretending I'm stupid, and maybe I'll make him late to whatever he's doing next." We didn't really want to retain these customers anyway, as they usually didn't spend much money in our store! Watch out, and remember - it may be good fun for you picking on someone, but you never know when they may have "mental problems" and snap!