There’s quite a few possible additions:
*Social anxiety – a lot of us find groups intimidating, at least at first. Perhaps after a while that lessens as we get to know folk and begin to feel ‘one of the gang’. Starting all that from scratch…..
*The sheer hard work of getting involved. To feel one of the gang can take a lot of effort. Maybe you feel that you need to be seen to be active and committed enough to avoid being labeled a ‘lightweight’. Maybe you feel that only by working as hard as the most active are you making a difference. You mention legitimate peripheral participation regularly on this blog, so no need to say more
*Group culture evolves and changes and it can be a real effort to recognise, understand and then implement the new ways of working. For example you might need to learn a completely new set of hand signals – these seem to changing under the influence of US Occupy culture
*The equating of new to the group with having no relevant skills or experience. This is a real problem in some groups. It can, sadly, be rare for groups to understand that newcomers bring a wealth of resources, let alone invite them to share their experience, knowledge or ideas. The assumption is that the group is wise and the newcomer needs to learn. Maybe older men are credited with the possibility of relevant prior experience, but for a younger person, especially a younger woman….
*Ego. Let’s face it, it can bruise the ego to get back involved and see a whole load of dedicated, competent people who are doing just fine without you. It can remind you that first time around you played all the ego-games to feel involved. You left newcomers feeling excluded from the inner circle, and now you feel that way. Ouch!