Tescos, because without fail the shopping experience is appalling, and then there is the question of alleged lack of morals and ruthlessly unfair anti competition fun & games they supposedly employ.
Agreed - we spent a considerable amount of money with their Direct arm about 6 years ago and they took that as an opportunity to royally dick us about. It was genuinely like they were looking for ways to deliver ever worsening service. The in store experience is also shockingly bad.
Asda - even worse than Tesco. We used to get our shopping delivered and three weeks on the bounce they messed things up and each time they made a bigger hash of sorting it. The final time they "forgot" several key items - bread, milk, cheese - although they didn't forget to charge for them. Promised to send someone out with them, who never arrived, then denied ever speaking to us. Took a week to sort the refund out and no apologies at all.
Had the misfortune to nip into a branch the other week to find huge TV screens above the self service tills emblazoned with 'DO NOT STEAL' showing you scanning your shopping in full close up HD. Hateful place. I won't be back.
I avoid ALL Virgin branded products or services. Put up with such an awful Virgin Media "experience" for year after year thanks to "loyalty" discounts each time I tried to leave but in the end you just realise life is too short to be constantly feeding so called engineers a diet of coffee and biscuits, that you just don't want to have anything to do with them any more.
They are another company who will never get a penny out of us for their simple inability to install their own phone line, and the saga that went on for months trying to sort it.
Yorkshire Bank - despite years of being a loyal customer they used a short period of extreme financial stress to abuse their position on the slimmest of technicalities and then added insult to injury in the way they dealt with the complaint.