Michelle Hooper is among the one in nine retail and fast food workers who have experienced abuse from customers in the past 12 months.
Ms Hooper describes one instance of abuse she received while working at a drive-in counter at a fast food outlet in Sydney's west.
"We'd already closed and this woman came through and she wanted to feed food for all her kids but we had already turned everything off, and she screamed at me for more than five minutes about how I ruined her kids New Year's because I couldn't make them food," she told SBS News.
But the 29-year-old woman said it was all too common and her colleagues were routinely abused by customers for simply doing their job.
"There's people, they're bigger than you, they're screaming at you, they're swearing on you," Ms Hooper said.
"I've had people throw food at me, spit at the bench in front of me and I've been there while they scream at a 15- year-old.
"There's one other time when a fully grown adult man (screamed) at a 15-year old and people would think that it was acceptable."
Ms Hooper says the abuse has often left her in tears and as a result once suffered an asthma attack.
"One night I got shot with a pellet gun and afterwards I was a shaky, nervous wreck," she said.
A national campaign titled No One Deserves a Serve has been launched by the union for workers in retail, fast food and warehousing to stop the abuse and violence towards workers by customers this Christmas.
A national survey has found more than 85 per cent of retail and fast food workers have experienced abuse from customers.
Almost a quarter of workers say they have been subjected to verbal abuse every week and more than a third have felt threatened by a customer once or twice in the last year.
Shop Distributive and Allied Employees Association NSW branch secretary Bernie Smith said the impact of abuse on workers could be detrimental.
"We have members who are psychologically injured to the extent that it really takes them out of the workplace," Mr Smith said.
"We have people who are physically injured with knives pulled on them being spat on having groceries thrown at them.
"The range of abuse is severe."
It is hoped the latest campaign will ensure those working at the checkout can enjoy the festive season.
"We're asking people just take your time, think twice, check your attitude before you get to the check out because nobody deserves a serve when they're here to help you," Mr Smith said.
"Because Christmas can be a particularly bad time of year for retail workers suffering customer abuse."
