It is the job of supermarkets to get you to buy as much in their shop, rather then their competitors, as they can manage. It is our job, as customers, to be very clear about what we want, how much we can and can’t afford. And perhaps, most importantly, to spend mindfully. It’s absolutely fine to fritter and spend your way around town if you’ve decided that’s what you are going to do today. Not so much if you can’t afford to and it ‘just happens’.