I work as a cashier and I dont really see why any cashier would give you a dirty look, as its the company who is losing money and not them. I ring up 25 cent - $1 things all the time and I dont think twice about it b/c i use my card most of the time as well. I do have customers apologize to me for using their card for small purchases and I always wonder why they are apologizing b/c its easier for me to stand there and let them swipe their card than it would be for me to open the drawer and count change back to them.
I am so used to my stores liberal policy that i didnt even think about it when i wanted to get some copies and the guy was like "a credit card for twelve cents worth of copies, you've got to be kidding me"
I work as a cashier sometimes as one of my many part-time jobs and I always think about the transaction fee whenever someone runs a card for a transaction under $5. It's just one of those little facts that I can't help but be reminded of, and while I most certainly hope I am not giving rude looks () it does kind of matter in the sense that most companies have to account for that fee while pricing stuff (why everyone prefers cash!!) so it makes everything more expensive. I'm terrible with economic theory, but does this, in effect, make cash less vaulable?
Like if you buy a drink and it's $1. You pay with cash, store gets $1. You pay with a credit card, and store only nets in 70 cents.
On a side note, I suppose that working as a cashier allows me to see how terrible credit card debt can be... I have people come through my line who get their cards denied or will talk to me about how they opened a store card and then maxed it out and are still trying to pay it back. And then sometimes people who owe thousands in debt will come in but just make the minimum payments each month. Not something I ever want to get myself into.