By way of an anecdotal example: I know someone whose father thinks there is nothing wrong with clicking his finders and yelling "BOY!" at a waiter to get their attention. Except in Italian places - there it would be "Luigi" rather "boy". I bet he consumes a lot of spit when he goes out for a meal...
For many reasons many people out there are dicks. I might well be one of them if I'm honest with myself, though not one of the worst by a long shot. And if you work in retail or catering you are likely to meet far more than your fair share of them. Remember: most workers in a shops or restaurants deal closely with far more members of the public in a day than most of us encounter closely enough to notice in a year.
I'm assuming you meant "such people exist", but if so, that's probably the most accurate typo ever :)
Nearly all waiters/waitresses I've ever come across in restaurants have been fine or better, and the people in my local Chinese and Indian takeaways are really, really friendly.
But Dominos and Pizza Hut drivers? Eugh, they're all (and by "all" I mean "all who work in the two shops near where I live) really grumpy and sometimes even rude. If I order a pizza, there's a 50% chance I'll have to actually concentrate on not yelling at them. I've twice felt the need to complain to the Dominos franchise owner about a driver, something I've never done in any other industry, not because I wanted to get back at the driver, but because the service was genuinely so poor that I felt they deserved to hear from me. For example, if someone orders a Pizza for delivery, the driver should try and deliver it, not just decide that ringing the bell is too much hassle and that it would be easier to leave the pizza outside the door getting cold.
Probably just a coincidence, but an interesting one.
Perhaps its only the crazies that can stay with the job for more than a short while.
this is an excellent anecdote, lucky the waitress f'd up.