Hi Tom
Hee Hee, I know, the very act of sitting is the good bit
For me not having to go back round any of my unresolved attachments and blockages anymore is "good"
My dark night was pretty intense and sometimes I wondered if I would come out of it as a functioning person.
So for me a good sit is one where nothing unpleasant happens, meditation is after all meant to be enjoyable, and a sit where I can just calmly be.
I do understand every sit is good as it has a lesson even ones where very little happens or where impediments or difficult experiences arise.
One of my most insightful sits was unpleasant and involved a dream like sequence where a guardian/hellbeing was breaking the bones in my ankle, knee and hips due to a bad karmic action I had taken (killing a different hellbeing). That sit showed me I was holding onto ego pride about my perceived strengths and achievements as I had killed the other being as it was evil and a cause of suffering. Of course in "reality" I would not kill anything but in the dream I did. Also i think that it was a lesson that suffering is good in that eventually it brings the mind towards a path of liberation.
Also for me a good sit is one where I learn something or see something new (I am a scientist after all).
But to be honest now I am not so sure what a good sit is really. Before I was all fired up with impermanence and the wish to achieve stream entry in this life so I could be a better person and better able to try and do something to stop the suffering of myself and others, so any sit where I felt I was "making progress" I liked. Now I dont really feel any sort of urgency anymore in my sits. Sometimes they seem pretty boring though, sitting in equanamity with a clear mind is pleasant but not exciting.
Simon