Hmm, re-reading I realized that someone could think that I was painting a bleak picture of retreats. Actually my very limited experience is that retreats are very sane and very good things to do.
I've been on some "self-development" courses that had a retreat-like structure, but kind of danced around the idea of seeing experiences arise and pass away. I found those to be very difficult to navigate because of the false-certainty it created about experiences/content and a psychological self.
In contrast, there is something very sane about creating a retreat context where there is freedom to see the ambiguity, chaoticness, and fleetingness of what is happening every moment of our lives. This freedom to see is a priceless thing and it is very hard to find that freedom in every day life.
What I'm saying is retreats can be time very well spent.