Imagine if you told them to have a good day.

sounds like she could've used a happy pill or two. *wink wink*

How the hell does something like this even happen?

let that be a lesson for you. don't be nice to the customers

Please explain how it caused you to almost lose your job..follow up!

"The customer is always right". Bullshit. Customers are generally assholes.

"Welcome to Costco, I love you. Welcome to Costco, I love you. Welcome to Costco, I love you."

Gotta love the holiday season, always brings out the best in people

Customers can be completely insane. I frequently work at a self checkout and one day I helped an older woman. By "helped" I mean I generally check 90% of the people out there like it's not self checkout. Anyway, I scanned everything, hit pay now, told her the total, and slid her card. The woman then got pissed because I wouldn't also sign her name for her. She literally threw the pinpad at me and said she "could take me" all because I didn't do the one thing that is against store policy, her card's policy, and probably the law. Moral of the story: You are not alone, OP. I feel your pain.

And that's why I utterly refuse to work retail. People are in general insane, mean, rude and depressing. I got enough of that in my life.