Customers that say they don't want items anymore at the register

Im a cashier at a clothing store. I swear this annoys me so much every day. I'd understand if it was one thing or maybe two that you misread the size. But not fucking 15+ things just cause. I swear it doesnt register in my brain why people do this. Do they really just throw a bunch of shit in the cart blindly like "ok now let me go tell the cashier I dont want half of this shit instead of deciding and putting it back myself before I get in line" Now I barely have space on my counter to do anything and I gotta void all the items on the computer and sort the shit out and put it back while you stare at me like I'm an idiot