Its a reality that people do tend to treat "nice" people by walking all over them.

I prefer to try and be a nice person, but set firm boundaries.

I recently helped someone by listening to her problems for a long time (she was going through a divorce). Because she spent so much time talking to me, I mistakenly believed she was a "friend". Then, when I needed help from her, she lashed out at me for no reason and informed me coldly that we were not friends. It turns out she was just using me as a shoulder to cry on for a while, and then she moved on. She found other people to use. I've since learned she has a history of moving on, she has no long term friends, she gets mad and holds grudges against people. She moves on to new people, then gets mad at them and stops talking to them. Its an endless cycle in her life. But the only reason I found out all this, was because I happened to know someone else who knows her. She did the same thing to this person.

What I've learned is that I will never again try to be someone's therapist, and if they have emotional issues that are unresolved, I will just tell them I am not a licensed counselor and don't have the background to deal with their issues. And leave it at that.

I've also stopped loaning money, giving expensive things to people, or letting people borrow my stuff. Because they read this as "she's easy to walk all over; if I got this out of her, what else can I get from her"? That is, unfortunately, the nature of some people. They are very simple minded and believe that if a person does something nice for them, they can get more and better out of that person.