The thing that I really enjoy about the Jams is the fact that every once in a while an experiment turns out to actually have sounded pretty good. You can't really tell how a number sounds when you are up on stage playing. I mean, you can tell when it really stinks, but you can't tell if it's any good.
The next day when I'm listening to the recordings from the previous evening I am occasionally surprised to find a number or two that hold together quite well. Realize that in a jam, you frequently have a group of people of various skill levels that have never played together, playing something for the first time.
Those rough gems are never as polished as what you would hear in a regular gig, but sometimes they are just good enough to let you hear the potential for a good piece of music.
That's what keeps me going back to the jams.