Just been to Lidl for s few things.
Saw some mince ,best before 24th but at 30% off would be fine for tonight /freeze. I picked up 2 packs and paid for all the groceries. The total was way above what I mentally tallied so I went through the receipt.
I found that although the discount had been applied correctly there was a sum added for each pack I bought. I queried it with the assistant who said -yes that was supposed to happen !!! 
Apparently there was a buy 2 for a certain price (which was not labelled anywhere on the meat fridge) and the computer decides that you can only have 1 discount at a time. So, if you buy 2 packs for £2.69 each ,less 30% which is 81p each the computer then adds 62p each ( which was the original discount) making a huge saving of 19p each (but cant be arsed to work out what the percentage is) .
The assistant and deputy manger were very polite and helpful and agreed that perhaps it was not the best discount . The assistant offered (much to the chagrin of the queue) to put the packs through individually which would then apply the discount correctly but I was past caring and asked for my money back. I was out of the shop before realising that they had short-changed me.
Ever wished you had just not bothered.