Mistaking another customer for a worker is always a disastrous experience: You're embarrassed that you made a mistake, and they're confronted by the fact that someone thinks they look like a “lowly” retail worker. Depending on how much of a jerk the not-retail-worker customer actually is, they may just brush it off and leave you to stew in your embarrassment. Still, there's also the chance they explosively take offense to the situation. When this happened to this blind customer, who had mistake…