I’ve definitely gotten angry about a situation while on the phone with a customer service rep, but not with the rep themself. I make it a point any time I’m audibly angry when on the phone to state that I’m angry at the company, not at the person I’m speaking with, and that I understand that it’s not their fault. It seems to help a lot; I used to work in customer service and I sure appreciated it when people made that distinction to me. It’s okay to be upset, just don’t take it out on a CSR.