I was in this cafe today and I overheard a lady having a conversation with the cashier: she had a sandwich yesterday but she only had her card and she'd come back in today to give the money she owed. The cashier looked at her blankly and said she didn't remember that from yesterday so she should keep her money. The lady pushed a tenner across the counter and told her she owed them money. Then some other cashiers came in and said they'd already cashed up yesterday and she should really keep her money. 'We won't take it, go and buy something nice with it' they said. It was a really sweet exchange on both sides - the lady was really honest and the cashiers were really kind.