Understanding Love

Recently I've been thinking about the "word" we call love.  It's not the "word" itself that gives me problems, but it is how we define and express it that's disturbing.  In all honesty, it seems that this thing we call love is very conditional which goes against what love is suppose to be about.  I've often thought to myself, how does God continue to love us in spite of who we are? If we struggle to love those who continue to disappoint us, frustrate us, make us mad, etc... is it possible to get to a place in life where we can love our fellow sisters and brothers unconditionally or in a way that pleases heaven?  Share your thoughts with me, I would love to hear from you.