being me is not good enough?

I never learn from my past mistakes.. or at least it feels like I dont.
Sometimes I feel like I'm naive.. I'm too trusting and allow people to take advantage of me. and then I become disappointed and angry when they dont deliver to my "standards" of behavior because that's what I expected in return.
even though they never "agreed" with my expectations.

it makes me angry at myself, it makes me angry at these individuals and makes me sometimes doubt if getting to know new people is actually worth it. It feels like I'm just loosing more than I'm gaining.
Or at least that's how it feels now, at this very moment. Just when I have been having a negative experience yet again with an individual I thought was worth "keeping".
I was wrong.. and I learn the hard way.

This is not the first time I'm angry at myself because of this person, and it's not the first time I'm angry at this person.
How can I overcome this believe that people are by rule kind hearted and want you well?
When in real life people think about themselves and their gains in the relationship. how much can they get away with this time without giving anything back or actually investing in a friendship or a relationship?
Why does it seem that I attract these type of people?
and why the f**k cant I learn that it's never as it seems, they dont mean what they are saying and I just end up without a friend and loss of integrity and/or positivity.

I know that this is not true of all people, but like I said.. it feels like I'm attracting all the "wrong" type of people in my life now.. and it's making me feel that I should just keep to the current friends I have, not open up, not take chances and not allow people in.. because I'm too open when I start.. I'm too needy if I can say that. and people cant handle it and leave, and take their words and promises with them..
good riddance I guess!
lets see
-with love-