MaryAnn-
Have you ever been in a convienence store? Half the time the person behind the counter can’t even be bothered to tell the the total cost!
As long as they talk to me though I don’t care what they say. I don’t expect them to be excited to take my money. And I do appreciate when they at least make some effort at being polite, so I like you’re welcome!
I’m stunned. “You’re welcome” pisses you off? I never even considered the possiblity that this could be construed as rude, mainly since it was taught to me as an example of good manners.
JEESH!
sometimes one of my kids will do something annoying, and I say " Oh, thanks alot"
and they always say sweetly “You’re Welcome!”
maybe its just a reaction…
I’ll admit I was a bit confused halfway through reading this - I’ve always just assumed that when you say ‘Thank you’, there is an automatic response that, ummmm, automatically follows. Maybe I’m dating myself but, as Dogbert said, it’s not like anyone else would date me. Thank you, I’ve always wanted to work that one into a conversation. Oops, sorry, I digress.
Anyway, my shopping experiences are either: get in the store, find what you want, pick the shortest line, pay for it, leave; or, find a clerk, ask for opinions/advice/whatever, listen to the clerk, enjoy the shopping experience. In the first case an obligitory ‘Thank you’ followed by ‘You’re welcome’ is part of the experience and I really don’t notice it one way or the other. In the second case, the thanks are genuine (regardless of which one of us starts it), and the welcome is also called for.
I think that this relates directly to the OP - it isn’t the words, it’s the mood. If the clerk feels that they have to (or are required to) say something, just ignore it. If you think the clerk has actually done something for you, put some feeling into the situation and enjoy …
-E-
I work in customer service, for my municipal government. Trust me when I say we rarely get thanked by anyone. But when I do, I make sure that I am looking directly at the customer (eye contact is important), I smile brightly, and say “You’re quite welcome! I’m glad I could help.” When I work on the phones, I do this as well…customers can HEAR a smile in your voice as well. On several occasions, after an exchange such as this, customers have asked me my name again (I always identify myself when I answer the phone), and ask if it’s alright to request to speak to me if they ever have any other reason to call back. I always tell them my name, and how to spell it, and that yes indeed, they certainly may ask for me specifically. If I can give a customer a good experience in dealing with the government, then I’ve done my job.
Does anyone remember when “excuse me” meant “I’m sorry to bother you, but. . .”?
These days “excuse me” can take on three different meanings. If you say it with kind of a haughty tone it means “get out of my way you maggot-infested sack of dog excrement”. If you say it in a sarcastic tone of voice it means “so I spilled my punch on your stereo-- who cares?” And if you sound apologetic it means “I’m sorry to bother you, but. . .”
Maybe that’s what’s happening here. Maybe the problem with “you’re welcome” isn’t the words themselves but the tone of the voice saying them?
“The problem with reality is the lack of background music.” – Anon
I think “excuse me” actually meant “I’m sorry to bother you, but…” until Steve Martin did the “well excuuuuuuuuuuuuuuuuuuuuuuuuuuuse MEEEEEEEEEEEEEEEEEEEEEEE” thing. After that, everyone just copped an attitude.
Frankie
Yes, I have and I’ve never had the problem that you’ve described. 
I’ve never dealt with a clerk with an attitude.
MaryAnn
Sometimes life is so great you just gotta muss up your hair and quack like a duck!