You're not an easy target.
There's nothing wrong with trusting what people tell you until you know they lie and are liars.
It's better then going around not trusting or believing anybody because you're afraid of being lied to.
Seeker is right when she said we learn from experience.
I think the test of time is the best preventive medicine. I've been played mostly when I was rushing into something or trying to rush out of it. I trusted too quickly because I would recieve something in turn that I wanted. "Look before you leap" comes to mind. At least with me. I'm not saying that you or anyone else does this.
I'm sorry you feel taken, Curley. Just remember, there are a lot of people out there who deserve and want to earn your trust for all the right reasons.