This happened in the early 2000s.
I worked at a chain family-owned grocery store. I had been working through the ranks and was head cashier at the time, which basically meant I figured out breaks and handled customers when the cashiers couldn't.
This fine summer afternoon, I spot him, this creepy guy. Anyway, he was in line to one of our cuter cashiers, who, as soon as she saw him, flashed her checkout light signaling for help.
Backstory: This is the disgusting part, and I cannot deny or prove this; however, I had heard from several sources that this guy liked to go into the checkouts of cute girls, stare at them for a bit, then go home and while staring at their name on the receipt, jerk off to them.
Anyway, back to the story. As I saw the cute girls light flash, I knew immediately what to do. I waited a few moments until the man was committed to the line, then bee-lined it straight to her register, told her to sign out and go on break (wasn't really her time to go, it was more of an excuse to not arouse suspicion).
Got him - I knew the man had already placed his half gallon of milk and other sad groceries on the belt, and couldn't escape. His smirk deflated in front of my eyes like a child opening a box for Christmas and it revealing a subscription to Field & Stream magazine.
I gave him the heartiest "Hello! How are you today?!" smiling and making eye contact. Here’s where I decided to push the awkward meter further. I decided to maintain eye contact the entire time I rang him out.
He mumbled something incoherent, but I didn't care. I was beaming on the inside. However, my job was half done. I still had to ring him out.
I must've fumbled with that box of cereal for a few more seconds than I should have, but I was not going to break that eye contact. I literally felt around like a blind man, while I maintained my eyelock onto him. Oh, he started grunting and looked away multiple times, but I felt like it was my civil duty to make him as uncomfortable as he made those girls.
Thank God I had a bagger to help otherwise I would've had to bagged his items and break that eye contact. After ringing him out, for what felt like forever (was really only 5-10 items), I handed him his receipt, and when he went to grab it from me, I maintained a firm grip on it, looked him dead in the eyes, pointed to my name on the receipt and said:
"In case you didn't know, my name is DrWeeGee, I hope I provided you with excellent customer service."
I let go of the receipt and watched him twitch off. I think I saw a vein on his forehead explode. The cashier came back and thanked me for helping her with him.
Aftermath: Other cashiers and baggers apparently saw this whole ordeal, and watched the entire thing transpire. One of the other baggers came up to me later on saying he saw the man throw the receipt out when he got outside.
After Aftermath: A few weeks later, I saw the man in queue for another female's line. Immediately, I went up to the cashier and told her to go on break, flashing him a wink and a smile. The man (I kid you not) placed his items on the floor, turned, and walked out.