My latest, and most satisfying was recently. Around Christmas time, this lady that reeked of "let me talk to a manager" came up to my register. I said hello and the formalities and asked her if she found everything ok. She didn't even acknowledge me and instead turned her phone to me and promptly pushed it to my face saying that she had a coupon for %50 off any item in store. I backed my face up and looked at the screen for a moment, and in the bottom corner it reads "not an actual cupon, must register with website". I study it more and I realize it's just some fucking picture she pulled up off of google. I inform her we can't do that, and why. She just stares at me as if I hadn't finished talking. And of course asks for a manager. So I call him over and he confirms my story and he leaves me to deal with it. Now there's a line. It's near Christmas, at a toy store. So she looks back and says "put this aside for me, I'm going to find another cupon." AND PROCEEDS TO SEARCH GOOGLE IMAGES FOR CUPONS. So I finally get through with my line and it's time for my break. I pass the still googling lady off to a customer at the electronics desk. After my break, I come back up and I look up to the electronics desk and see there's no one there but the lady standing nearby. She does the Scooby-Doo villain look to the left and right, and just scoops up her item from behind the counter and puts it in her basket as she's walking towards the door with a cart. I walk up to her with a huge smile and ask "did my coworker help you out with that transaction already?" She just gets a kind of shocked but controlled look on her face as her eyes dart left and right, and she finally mumbles out "..was waiting for someone to check me out...but.." and she trails off. So I tell her I'd be happy to have someone help her, and I radio over to my electronics guy to head back to the counter. He comes over and he sees the item in the cart and looks at it, behind the counter, then to me. I just smile. It's nice when you get to catch people with their pants down sometimes.