Maybe some of it is that we are all different, Steve? For me a session is relaxed and (with the proviso that you know whatever is going round) you can come or go as you please - at least mostly, I'm no session leader (or usually not skilled enough to be that and with a limited repertoire, although aim to fit in) but sometimes you want to start a set or two going. Rarely for me but sometimes you can find yourself having to step forward a little more but you go with the flow (some of which can be your own). Things works themselves out on the night.

It's (to me anyway) quite a contrast to working out what you might do on the night, worrying about when you get called to do it, etc. And while it's nice to get applause and even better, to feel what you did really did go down well, I'm less interested in that side.

Others of course may have different intrests, eg. the response or introducing others to something new...