Signed off on a brake and suspension job in writing, drove off happy, then rang the bank a fortnight later to say the work "wasn't needed." We had the worn parts, the signed authorisation, and the invoice. The bank still took three months to agree with the people who, you know, had evidence.
Brought the car back in demanding a "warranty repair" for a dent that had, by his account, mysteriously appeared as a direct result of work we did six months prior — on a panel we never touched. His own dashcam, which he'd forgotten was still running, later showed the actual moment of impact: a car park, several weeks after our job, and nothing to do with us whatsoever.
Booked an MOT slot. Cancelled it. Rebooked it. Cancelled it again. Repeated this dance four times over a fortnight, always within the hour before the appointment, at which point we stopped holding our breath. Fifth booking: total silence. No show, no call, no acknowledgement that a bay had been sat empty on his account four times running.
Fifteen-year-old car, north of 150,000 miles on the clock, in for a routine service — and genuinely furious afterwards that it hadn't been resurrected into something showroom-fresh. The electrical fault we flagged verbally, wrote on the invoice, and quite possibly should have had tattooed on his arm was, shockingly, still there.
Came to collect his van after a clutch replacement and announced, with total confidence, that the engine "sounded different" and we'd clearly fitted an inferior part. Declined to hear about the actual diagnostic report. Volume increased in direct proportion to how little he understood what he was shouting about. Asked to leave twice. Left once, eventually, on the second attempt.