You shouldn't treat adults like kids.
Celica thinks her coworkers are idiots because they can't work a computer properly.
Celica wants to explain how to use the computer to her coworkers.
Celica explains the computer to them but without using childish tones.
Celica explains the parts of the computer to them like they are little kids.
Celica's coworkers thank her for the lesson and can use the computer better.
Celica's coworkers think she's being condescending towards them.