Long time ago had a really painful client. Everyone had an attempt at training the said client. However, the client just didn't get the system at all and kept asking lots of questions.

It got to the point where one poor developer had to make a set of screencasts of him using the system and performing basic operations.

I recall how absolutely insane it was that in addition to the hours of trading time we had provided we were sending him links to video files we'd created.

It was literally face palms all around and so bad it was sort of funny.