I also work retail, although most of the time I'm behind the scenes rather than on the shop floor. I've never had to deal with a customer that didn't bare with me, or at least didn't act annoyed. Speaking on the phone is the worst though, rather that a stutter where you keep repeating the first few sounds of word, I tend to get held up on a word for no reason at all, so if people ask my name over the phone, sometimes I can say it right away, other times I'm left stuck, waiting for my name to come out but nothing comes out, and on the other end of the line they think I've hung up.. It's for that reason I just say the first name that comes into my head, so most of our suppliers don't actually know my name =/