99.99% of the time, the customers don't give a shit. Sure some might try and hurry you on because they're fast talkers, but that would be happening to any slow talker and not because you stutter. 0.1% of the time I get asked about it with a genuine curiosity. Only a few times I have asked if I had one, and once someone said their son also has one and she couldn't wait to tell him that she talked to someone who worked in a call center with one.