It depends on the individual.  Myself, not being the smartest
person in the world, I would have trouble taking a crash course in
anything, especially something like Photoshop.  The reason I'd have
trouble is because once you show me a tecnique, I need to use it on my
own for a while, to get the hang of it.  If I'm sitting in a
classroom, and the instructor shows me 20 techniques in one day, I'll
forget everything he showed me.  I may remember one or two things, but
I'd forget most of it.(old age might be a factor here <g>)
     I frequently get a flyer in the mail that offers a 2-3 day
Photoshop class.  You can sign up for either 2 days or 3 days, and
each day is 8 hours of classes.  There's no way I'd get much from
classes like that.  I need to have a one hour class, go home and play
with what I learned in that class, then go back the next day to ask
questions....kinda like they did when I was in college.
     Heck, I'll even read about a new technique here in the group, try
it out for a few days to get the hang of it, but two weeks from now,
I'll forget how to do it.  I'll always bookmark new techniques, or
print them out, that way if I forget, I'll have a place to find it.

Talker