As a quick aside to Nasat: having selfless ideals is not incompatible with taking life by the scruff of the neck; just ask the founder of any charity you care to name! Using your ideals as a reason not to take active charge of your own destiny does them a disservice. Even (especially!) if you want to change the world, you need to be able to live well in its current incarnation. That requires making, and taking responsibility for, your own choices.
A sense of entitlement without a desire to have to choose outcomes to fulfil that sense (pretty much your current self-reported situation, in a nutshell) is tremendously disempowering.
Thanks for the advice,
Holdfast.

I do acknowledge that there's a disconnect between the way I seem to "expect" things to work, or believe they should, and how they actually do. Unfortunately, I'm not geared towards asserting myself or taking control of a situation - I'm a natural subordinate, not a leader; more than this, I have practically no ambition. And I'm not sure my sense of what matters in terms of self-respect and self-discovery matches most people's idea of what is "empowering".
I'll work hard and make decisions as to where I'll apply myself, but when it reaches a certain point I'm looking for someone to assign me a position and, unless I'm really put-off by it, I'll slot in. It needs to be a position that makes good use of what I have to offer, though. And I won't take a position where I'm truly unhappy unless it's an emergency, and then only temporarily. But, basically, a working life where I have to make all the choices isn't one I'm comfortable with.
I'm not saying I think what you said is wrong - I think it's wise, but it wouldn't work for me. It's a outlook I often think it might be nice to have, but it's not one I'm geared for. In a world where the individual has to shove forward under their own power of ambition, or their own desire, their own drive, I won't go very far. But I have traits and skills and ideas and work ethics that would be useful...surely it is wise for some of those more equipped for the world as it exists now to turn and take me in, so as to make use of these, and so benefit the whole, and themselves?
I mean, I'm practically begging to be used here, but it seems humanity doesn't want to. Exploit me, dammit!

I don't see the sense in letting potentially useful resources go to waste. I know most people have moral or intellectual objections to a mindset of passive "make use of me" rather than active "I'm going to forge my own destiny" - and I certainly respect that - but surely that mindset isn't the
primary criterion? If I walk in the door and make myself known, I need someone there who is willing to consider whether or not I could be of use. And I'm not foolish, I understand all too well the myriad ways in which my vision of what's best for me doesn't match up to how the system works. But that system and I just don't seem compatable. Therefore I lose, and because any useful or productive role I could play never materializes, potentially society loses. And then I'll have failed in my duties and I lose again.
I mean, basically, I'm not ambitious and I'm low maintenance. I'll be happy enough doing minor jobs to pay my way, and earn a modest keep. But my sense of duty doesn't allow for that; it keeps insisting I do more, actually realize my potential and put it to use. Actually do good on a larger scale than simply "be good to those around you as you live your supremely low-key life".
And of course I'm aware that you can't sit around and expect employers to call you, you have to get out there and apply and argue a case for yourself. I'm not lazy (I wouldn't have done so well in education if I were); I'm simply not assertive.