Albatross,
Oh, I love philosophical debates!
I would consider myself a "realist", but again.. reality is based upon perception.
I love your take on this, however a few points I'd like to make:
You are not responsible for other people's actions and you can not put blame ( or rather, should not) on yourself for what others do. To take responsibility for how others treats you is not, in fact, your responsibility.
We can not change others. People can only change themselves, if they truly, truly want to.
On another note, dependence on other can indeed be a bad thing, but at the same time I strongly believe that you should have at least 1 or 2 people whom you can really depend on. For instance, I know that there are people here who I can depend on for insightful and credulous responses. I know that I can depend on my boyfriend to be there for me, when I have no one else.
This makes me strong and helps me get through the tough times. Even the ocean is dependent on the sands to keep it in place. And like water, peoples levels change.
While our expectations of people are in fact NOT their responsibility, if you try to remain truly unbiased in a new relationship with someone and try to study who they actually are, I think you'll find that oftentimes people do "put up a front" and try to pretend to be much kinder person or a much more of a person they think you'd want them to be.
Their own expectations of your behavior fault themselves and in that essence, both people are responsible. That's why I try to stay true to myself and be up front about who I am, and try to be open to who other people are.
I'm not saying I'm perfect, because I'm not by any means. I just try to not have any expectations when meeting a new person, if I can help it.
Of course, this is all my opinion and open to interpretation. :D