Have you ever noticed that no matter what retail store you shop in (including grocery stores) at whatever time of the day you shop that there are never enough cashiers? They do this on purpose!
Why? Because as you wait in line you look at the magazines on display, see lots of little things you might "need," decide that you could use a candy bar or a bottle of pop. Those items aren't there by mistake! And as you keep dropping just-one-more-thing in your cart you are adding more to your bill.
Think about it this way:
Add one magazine (avg $5), and a bottle of pop ($1.50), and a candy bar ($0.69) to your cart and you've added more than SEVEN DOLLARS to your bill. Do that once a week and that's over $360 a year! And think of how many calories that you're adding to your waistline!
And this is another reason to shop without the kids. They want gum and cookies and potato chips and little toys (all of which are displayed at a child's-eye-level) and when they cause a scene when parents say No, what happens? The parents give in. More money gone from your wallet.