I am speaking of people who answer the phone for a business and schedule appointments, take payments, and answer business questions. Often, if a minor issue comes up that may slightly "inconvenience" them (such as having to look something up or having to stop and think logically about an issue and respond back), they become rude, snarky, frustrated, insulting/abusive, and/or just unprofessional.
Most phone shop scenarios don't involve a "problem" situation. But, I find that often a person's nasty side comes out when they are required to take a little extra time or effort to do something perhaps they were not expecting. Or, it can emerge when there is a "dispute" about something that is legitimate and related to their business services.
Each time I've been given rude responses - all the way to a crazy woman I encountered, who flipped out into a psychotic rage and seemed to hang up on me (she said it was accidental, but the timing was shortly after she SAID she was going to hang up on me) - I wished I had been shopping them or recording them (my state has legal single party consent).
It'd be neat if ms companies designed programs that tested how employees reacted to slightly elevated "pressure" situations. Maybe shop them to see how they handle a complaint of service, for example. I think I made this point in a separate thread once, but since I came across a crazy woman recently in a customer service position, it triggered my thoughts on this again.
I think every two or three months, I'll encounter a very unprofessional person by phone. It's maybe not the norm, but I feel there is a significant percentage of such workers who are like this and am continually surprised they have not lost their jobs.