Remind me to never get a job in customer support..
I already hate dealing with customers at my job. Let alone dealing with it back and forth.
I worked in a Vodafone store (an agent, so not an official store) in Ireland for about 6 months. It is hard to describe the sheer hatred and loathing that customers confronted me with on an almost daily basis.
Vodafone, like most massive corporations, have a TERRIBLE customer service history. Often, customers came into the store because they had gotten sick of being dicked around by Vodafone's customer service labyrinth.
A lot of the time I sympathized with their plight, after all, I think all of us at some time or another has had to deal with a phone/utility company over the phone and it can often be a nightmare. I would try help them as much as possible and handle the complaint for them by cutting past some of the lower level reps to get to managers etc that could actually sort something out for me over the phone. Which took a bit of doing mind you, as their reps were about as helpful to us as they were to the customers, although it wasn't really their fault either as they had no power to do anything. I gradually got to know which people could actually get things done, so I got pretty good at getting problems sorted after a while.
I have had customers call me every name under the sun, refuse to leave the store, smash phones on the floor in front of me, threaten assault, threaten legal suits and all manner of horrible shit. These people never seemed to understand that A) I was not the cause of their problem, B) I was probably the only person who was genuinely willing to help them with their problem, and C) I was a human fucking being with you know, feelings and stuff. Once I even had to tell an old lady to leave the store because she busted her way to the front of the queue and started tapping her keys on the counter in ignorance, trying to get me to hurry up while I was dealing with someone else's contract. I asked her politely to wait her turn and she started screaming about how the coverage in her area was terrible, as if we somehow had control over that, calling me a scumbag and a knacker, saying that I was the reason the whole country was going to hell (oh the irony).
ALWAYS treat people with respect and patience. It works both ways. I would bend over backwards to help nice customers (even though officially we were supposed to give them the customer service number and get rid of them as soon as possible if they were not buying anything), but if they started insulting me for shit beyond my control, that was it. No more help from me.