Efficiency!!! Script first pls

Why don't patients think about efficiency? Customers walk around the pharmacy looking at over the counter products, taking their time reading the packaging, and then bring all the products to the counter thinking they're ready to pay so you start scanning the products. All of a sudden, they decide to hand you a script at that moment to get it dispensed. Like you know you could've handed me the script when you first walked into the pharmacy, so I could prepare it whilst you do your shopping in the store. Why do it the other way around and impede traffic?