There are parts in their description that point to unnecessary cruelty/meaniness.
> When the display did not change, the sales guy yelled at me; "WHAT DID YOU DO?!?!?"
At this point OP could have explained what they did, and explain why what the salesperson tried didn't work, and what should be done to fix it. They did not, instead they:
> So after watching him panic for a moment
Watched him panic, then showed that they could fix it (probably ego tripping), and then to rub it in even further, put it back on and walked away. Depending on the experience or seniority of the sales person this might have caused the sales person problems, a lot of stress, ruined a presentation, and real-life consequences, all of which OP disregarded.
There are pranks, and then there are pranks. This was unnecessarily cruel.
> When the display did not change, the sales guy yelled at me; "WHAT DID YOU DO?!?!?"
At this point OP could have explained what they did, and explain why what the salesperson tried didn't work, and what should be done to fix it. They did not, instead they:
> So after watching him panic for a moment
Watched him panic, then showed that they could fix it (probably ego tripping), and then to rub it in even further, put it back on and walked away. Depending on the experience or seniority of the sales person this might have caused the sales person problems, a lot of stress, ruined a presentation, and real-life consequences, all of which OP disregarded.
There are pranks, and then there are pranks. This was unnecessarily cruel.