It must have been around 92 or 93 that our system programmers group was tasked with delivering an application, because the application people themselves were swamped with more important applications. It was a kind of an early information kiosk app. We did this in a few days with two people, me and a good buddy, and everybody was happy. It used CICS, DB2 and Cobol, and a bit of S/370 assembler. It was fast. It contained the phonebook of our company and a lot of information pages that were refreshed by the HRM department staff. It ran fine and we had only one support call for it, ever. I took that call.
Pierre called, who was a fine drawer of cartoons, and a non-technical person. He complained that the application did not react very fast. I duly logged on to Omegamon, and saw that DB2 processed calls, most in about 0.2 s. I looked at CICS, and it ran OK. I looked at MVS and then at VTAM. I could not find the problem. But because lunch hour was approaching, I offered to hop over to the other building; it housed the restaurant and also the HRM department.
I popped my head around the corner, and spotted this particular performance problem: a very small trickle of smoke emanated from his terminal, forming a black-mini tornado going to the ceiling. Pierre looked a bit suprised when I yanked the plug from the socket in the floor, but he was happy again when we had a new terminal installed that afternoon.