Turns out I have practiced Loving Kindness for the past 15 or so years. Yes, some people have taken advantage of my kindness and it has hurt. In any event loving kindness is effective. It allows you to heal yourself and by extension heal others. Excellent article by Marguerite Manteau-Rao.
Marguerite Manteau-Rao: 4 Good Reasons to Practice Loving Kindness.