Customers who know they’re broke but still wants to buy half the store

The customers who will bring 10+ items to the register but only ends up buying half or less because they can’t buy all of it annoy me especially the teenagers and the adults. With kids, I understand because they may have enough for the subtotal but then the tax comes in and they don’t know anything about that. They usually have a parent, sibling, or adult with them to give them extra change. However, with teens and adults, a lot of them are working in customer service jobs in some way and they usually start as a cashier or cashiers from time to time. So they would know about tax and how to see the price of things and yet I still get customers who don’t even think to ask about the price of something before bringing all of their stuff up. They know how much money they have with them and yet are shocked they can’t buy all 5 dollar collectible item or 7 dollar headphones. I feel that people like that are overly impulsive buyers and I’m saying this as a tame impulsive buyer (I would only grab something I know can buy). Overall, be very aware of your budget