Why do we try?

How does it make you feel when someone that you care for, deeply, or for someone you are trying to help? When you try all you can to be there and all you that seems to happen is door shut in your face. Or you get ignored or most often cold shoulder. Why? When all you want to do is to be there for them, show you are different from the others that have taken and never given. We don't do it for praise or pat on back, we do it because of heart. 
I hear stories all the time on this subject and how others handle, some get to the point that they no longer care, others just walk away and most often, some, keep trying. 
I have been one of each of these at one time or the other and let me tell you, I have sworn off these type people but always seem to find them or they find me. I keep saying that I must have a sign "invisible sign" that only those type can see it and hone in on me, but as I sit and think about each situation, I find that maybe it's part of my purpose here on earth. I can't take it as a burden to me but as a part of what is good in me to give to another. If we keep seeing the bad there can never be any desire for the goodness or greatness in another. But do not get me wrong, there are times when you just have to walk away but it's not for the lack of trying. It's them. They are not ready, they still have a journey and they will take with them what you did/said to/for them and one day they will have that kindness or love;whatever you were chosen to help them with.
I will keep trying and know that every door/word closed,ignored,shouted is one closer to the day they will show someone love, friendship. 
Don't get me wrong, there is true evil in this world but at one time they/it did have a some form of heart. 

Thanks----