This might just be a US/Canada border state based problem, but I really hate it when customers get mad at me for not accepting Canadian coins in place of US ones because they "didn't notice" and claim that it doesn't matter. Like, this isn't Canada???? I don't understand what doesn't make sense to you as to why I can't accept your Canadian quarter??? It's not even worth $0.25 in USD ??? just why. y u mad (Current exchange rate is $1 USD is $1.33 CAD, for anyone curious.)
I don’t live anywhere near a border but I can imagine how frustrating that would be!