I've posted a few times recently on the restlessness that my husband and I are feeling about the world, which has led to him leaving the certainties of the public sector for the risks and rewards of the private sector and me to be using my maternity leave to try to figure out exactly what it is I think I want to be doing in my working life.
I'm trying not to post too much on the petty stupidities of the world around me and when I have I've tried to be fair (health visitors are a notable exception... they've really got my goat as I expect better from professionals so I've posted a few times on this).

I'm beginning to wonder if this has something to do with age.
30 is not middle-aged (at least please God I hope it isn't) but your thirties are increasingly the time for reconsidering your options.
My friend summed this up well last week as he and his wife moved from Surrey to Yorkshire, changing both their sectors of work as well as their jobs... "it's funny how ten years on from graduation we're all at it". Yes, I guess it is funny, but not totally unexpected.
Within 4 years I've had a big operation, chaired working groups for the Council of Ministers of the European Union, moved country, bought a house, moved job, lost a grandparent, got married and had a baby. I think the point is that by your 30s you have to be a real grown up.
Stuff happens and you have to just get on with it. Serious life-changing decisions have to be made and even if you've put them off all through your 20s, by your 30s something starts nagging at you. Yes, it might be your mother, but I think I mean a biological clock.
Remember 1500 years ago the average life expectancy of an adult was about 35 years. (and it brings you up with a jolt to realise that it's currently 34 for women and 37 for men in Zimbabwe today... very sobering to realise that while you may feel like you are only just beginning to sort out exactly who you are and what you want others have done all they are going to be doing not because they get knocked down by a car or whatever but because their lives really are hard).

At the same time the urge to rebel, to do things differently is just growing and growing. It's not just about age, it's about experience. By your 30s you've been around long enough to have a bit more clarity about what you think and a bit more confidence about asserting it publicly. Not in a teenage agressive way but in a making-a-difference way.
I found some posts on the isue of too-late teenage rebellion by my friend Angelfeet http://www.thoughts.com/Angelfeet/blog/rebellion-and-the-lat e-developer-97622/  and http://www.thoughts.com/Angelfeet/blog/dust-contender-for-mo st-boring-title-of-the-week-99464 . I know exactly what she means. I don't think now that I rebelled nearly enough.  Maybe that's because I had quite a comfortable life and didn't need to - nothing to really rebel against?

Anyway, there's a facebook group on this sort of thing.  New.  Needs content.  Please do check it out. "It's called I want to be a teenage rebel but I've left it too late". http://www.facebook.com/group.php?gid=41545675122