First of all, being a nice person isn't that hard. It doesn't mean you have to be super-friendly to everyone you meet, or even anyone. You just don't make snarky comments. You keep it to yourself. Maybe it's easier to say it this way: it's not hard to not be mean.
And believe me, I know how frustrating and stressful it can be to work in customer service. I've been there. I worked in customer service for years. I may be a nice person, but I admit I can be a very impatient person. But I always held my tongue when a customer wasn't being smart or wasn't being nice. It was hard for me sometimes, but I did it.
CUSTOMER SERVICE: LITERALLY THE NAME SAYS IT ALL. SERVICE TO CUSTOMERS. NOT SHIT ON CUSTOMERS.
I honestly wish any employees that are rude to their customers were warned or fired on the spot.
Today, I had a middle-aged male bus driver yell at me because I didn't tell him where I needed to get off. First of all, it's your job to tell the passengers that a certain bus stop is where a transfer is being made. He didn't say shit. My ticket also didn't indicate this. You don't yell at a 23-year old girl that she's going to make you late because you didn't do your job and tell the passengers this was a transfer. Also, you were already running late because your passengers at the transfer were literally taking twenty minutes to get on the bus, which made you behind schedule. Don't put it on me, jerk. Never taking Greyhound again if I can help it.
Another instance I want to talk about is not where I am just involved, but maybe a family member of mine received poor customer service.
About a year ago, my parents and I went to a restaurant in Boston. The waitress was really rude. When my mom asked a question, and the waitress didn't hear her, she said "WHAT?!" Okay, first of all, you don't say "what?!" to a customer, but ESPECIALLY one that is twice your age! Damn, have some respect for your elders. She was also snotty, impatient, and just moody. They always say leave your problems at the door before coming into work.
And the people who say, "oh, it's customer service, what do you expect", or "they've probably had a rough day", or "their job is hard" LITERALLY ARE PART OF THE PROBLEM. You're just making shitty excuses for people to be shitty to others. I bet they are the same ones who are rude to the customers themselves! Ugh!