Afterwards I felt terrible and made a mental note to keep my horrible manners in check and take a deep breathe before losing my rag.
I am not alone. More people are taking out their frustrations on innocent customer service workers, as we reported in Saturday's paper.
Some have been subjected to a raft of abuse. They have been stabbed, spat and sworn at and pushed and shoved and verbally abused.
Retail NZ chief executive Greg Harford said in-store violence and aggression had got significantly worse since the Covid-19 lockdown last year.
And Countdown's health and safety general manager Kiri Hannifin said its team members had been subjected to "more aggression, conflict and abuse than we've ever experienced in our business".
Four people were stabbed at its Dunedin Cumberland store on May 1. The attack left two staff critically injured and another two people needed surgery.
This behaviour is not acceptable regardless of the circumstances or how you are feeling.
I think Rotorua Lakes councillor and Whanau Ora leader Merepeka Raukawa-Tait knocked the nail on the head.
In an opinion column, she said in her view, the attacks and outbursts of anger were calculated in who they targeted.
"They restrict their shouting and haranguing to those who don't have the power to retaliate.''
I agree. It is easy to harass frontline store people and walk away. But it is not right. Walk away before you open your big mouth. I know I am going to.