I primarily use cash. I prefer it over card.
I don't understand why more places can't take cards! It won't be long until all the major supermarkets take contactless payments, not sure if it's just the massive transactions you can get going through them that stops them doing so currently. Contactless is a million times quicker than chip and pin, although admittedly at least 75% of the time when I go to do so in my regular Costa outlets it doesn't like it and insists on entering a pin. Same for my local Spoons, although that's more like 40% of the time.
My bold
Because it costs more for business to take a payment by card than it does by cash.
If you are paying by debit card, the cost is around 9p to large businesses per transaction. For independent retailers, the debit card cost is around 20p per transaction which wipes out nearly all of their profit margin.
Credit cards are usually even more expensive.
Compare this to cash, where banking, transportation, security and other costs are usually far less than the 9p debit card charges.
Businesses who get large numbers of low value transactions (i.e your grocers, pubs, book stores etc) would generally prefer you to pay by cash.
A Wad of cash does seem to hit the parts that other methords don't reach when buying a big ticket item such as a car. I have always got a bigger discount on cars when you can hit them with crisp £10 notes even over cheques. ( although I suspect the clearing time will be a factor here as well)
If it is a significant discount, it is likely that the cash misses the books and they are dodging VAT & Corporation Tax.