let me add my own to this one:

"The Always problematicos"
Always-problematicos are always calling, and calling. In fact, as you resume to work, the first people you remember are problematicos. These would call for every little thing, as if they are not meant to do anything by themselves. 'How do I do this?, how do I do that?' - even if you had explained it to them, only yesterday. They are the first to call-in to report an issue in the morning, they are the last to call before the close of the day. Worse, problematicos have an expert system problem database to which they always refer.

They would first go back and re-iterate in 'amazing details' what and what: when they last called, what you told them to do, what they did, whether the problem was resolved or not, and how they have analyzed right and left to conclude that their last case is definitely related to the new issue at hand. After making their case, they would feel they have given you all the necessary leads to resolving their latest-problem.

"The 'it is not working, it is not working'"
These guys just call in and report 'it is not working, it is not working'. Then you ask: 'what is not working', they reply 'the computer is not working'. They will soon start a very long story at the end of which they haven't made a point.

You'll finally have to ask such to start all over again, you'll have to ask them what they want to do and what they have done. The end of the story will be that what they have been doing is not related to what they wanted to do, yet they call in to report "it is not working".

example: trying to use Microsoft Excel to open the contents of a CD ROM containing video files.

definitely, 'it is not working'