What did you lose by taking the course?
Time, and maybe some cash.

I think short courses have most effect when afterwards we play around with the ideas (old and new) and when we associate with people we have met on the course.

It's like a staff meeting at work, they tend to be magnificent examples of collective stupidity. Somewhere in the 'no one of us is as dumb as all of us put together' category. But afterwards, everyone gets together in spontaneous, informal groups and THAT's when things really get done.

There is power in associating with likeminded people who all get together once or twice to discuss and expand on what you have all just been through or learned as a group.