There's a thing called satisfaction... and it feels great.

Why I would write my own slides/texts instead of already existing texts, has to do with satisfaction.
Yes, my slides might suck; yes, they might have loads of stuff missing.
BUT also: yes, I learned a bit more while writing and explaining; yes, it feels great that effort 'pays off'
If you are not confident about your material, how can you expect your pupils to listen to you?

I'm sure Lincoln Stein, dominus , Larry Wall and merlyn have great powerpoint presentations on the subject but what good are they if the person presenting them doesn't fully understand 'em? vaidhyakrish stated 2 things: He know some perl and he needed the tutorials fast. I doubt anyone will be able to answer all questions when using a premade presentation, on an unfamiliar topic.

as a sidenote:I told vaidhyakrish in the CB how I normally go about writing texts/prepping slides. He didn't think that was much help.
disclaimer (& update): I have no proof whatsoever that Lincoln, Larry, merlyn or dominus use MS Powerpoint for their presentations :)

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.