When a customer just wants to argue

Most frontline staff know the customer who isn't after a refund or a fix. They want the argument itself, and the usual advice is to let them get it off their chest.

The research on venting points the other way. New Zealand law also puts a duty on the business to protect the person standing at the counter.

What venting does to anger

American psychologist Brad Bushman tested the idea in a 2002 study published in Personality and Social Psychology Bulletin. He angered 600 college students, then had some of them hit a punching bag while thinking about the person who'd annoyed them.

That group came out angrier and more aggressive than students who'd sat still. "Doing nothing at all was more effective than venting anger," Brad wrote in the paper's summary.

A 2024 review in Clinical Psychology Review went further. Sophie Kjærvik, a postdoctoral fellow in Virginia Commonwealth University's injury and violence prevention programme, and Brad, by then a professor of communication at Ohio State University, pooled 154 studies covering 10,186 participants.

Writing in The Conversation in March 2024, they said "venting anger increased anger and aggression". What helped were activities that lower arousal, such as deep breathing, muscle relaxation and mindfulness. Even jogging, they reported, increased anger.

What a sustained argument does to staff

Overseas service research shows the cost lands on the worker too. In four experiments published in the Journal of Applied Psychology in 2012, a team led by Anat Rafaeli of the Technion Israel Institute of Technology found customer verbal aggression cut staff recall of what the customer had asked for and impaired their working memory. Participants who could take the other person's perspective were less affected.

A 2017 Canadian study led by David Walker, then an assistant professor of management at the University of British Columbia's Okanagan campus, analysed 434 customer service calls. Staff were more likely to be uncivil back when aggressive words came with "you" and

"your" and with interruptions. Positive words such as "great" and "fine" softened the effect, according to the university's release on the study.

"If customers change their language so that it's less about the employee and more about the product or problem in question, they can improve the quality of the customer service they get," David said in that release.

Here, Retail NZ's COMS Retail Crime Report 2024 found 99% of respondents, representing more than 1,500 stores, had experienced some form of retail crime or anti-social behaviour in 2023-24. Almost 40% of those incidents weren't reported to police.

Calm it down, then draw the line

The Citizens Advice Bureau's guidance for staff facing an aggressive customer starts with staying calm and listening, because "sometimes they just want to be heard". It suggests open body language, with eye contact that stops short of staring and arms left uncrossed.

If that fails, CAB says to ask the person to stop, then "politely but firmly" ask them to leave. Call 105 if they refuse, or 111 if you don't feel safe. Don't argue, don't turn your back, and don't touch the person or try to escort them out.

Employers carry the larger duty. Section 36 of the Health and Safety at Work Act 2015 requires a business to ensure, so far as is reasonably practicable, the health and safety of its workers, and the Act defines health as physical and mental health.

WorkSafe's guidance on violence in customer service areas lists a zero-tolerance policy, procedures that spell out what unacceptable behaviour is, and signs setting out what's expected of customers. ShopCare's December 2025 guide for retailers adds "clear guidelines on when to refuse service" and training in "knowing when to disengage".

The Trespass Act 1980 backs that line. Under section 3, a person commits an offence if they refuse to leave after the occupier warns them to, and the Act counts an employee acting with the occupier's authority as an occupier. The warning can be spoken.

Section 4 lets the occupier warn someone to stay off the premises, and coming back within two years is an offence. Both offences carry a fine of up to $1,000 or up to three months' imprisonment.

The Human Rights Act 1993 sets one limit. It makes refusing service on any of its prohibited grounds of discrimination unlawful, so the warning has to rest on the behaviour.

Before the next argument starts, write down the words staff will use to ask someone to leave, who's authorised to give a trespass warning, and when to call 105 or 111.