Take me or leave me, no just leave me !!!

Im just so disappointed, in other people but mostly in myself. To say ive been taken is an understatement. But really i have no one to blame but me. I really need to stop being so nice, only to get lied to , walked over, stolen from, and just really disappointed in humanity. I tend to give people the benefit of the doubt, well im learning that society is just not so nice. Im proving myself wrong but it is costing me an arm and a leg.  It seems to be that the more you give people ,of yourself and of monetary things, the more they take. Ive been more than generous over the years to people, only to have them steal from me when im not looking. I don't expect it from them because who would steal from someone that is giving you whatever you needed. Oh im sorry maybe its as simple as im giving it to you in a blue cup and you want it in gold. If its not the way you want it, its just not what it is. How can we tell these intruders from the friends and family we thought we were so close to. How do we know if there words are lies and they are making the "bad person" worse than they are. I mean one person can only have so much bad luck. Shouldn't i have seen that? Is there a test we should be giving? Or am i just to turn into a complete non giving non caring bitch in order to maintain my dignity and keep myself safe. I suppose so.  I guess when you find that you cant advance your relationship whether it be friendship or love , because normal everyday things are out of the question and your relationship revolves around one thing or another, usually something that is going to positively impact said friend etc.  In layman terms, they are using you for something and it takes awhile to get the gist of it.