God is Love.  God loves us so much.  We were created to love God and to love one another. ( John 15:12-13)  It is at times of true compassion for your fellow human being, that you will feel most complete, and you will know in your heart that this is what we are here on earth to do; to make a positive difference in each persons life that you touch.  It's not about "self", it's about others.  A friend of mine once said to me "if every person on earth (for just one day), did kind deeds for others, instead of thinking of themselves, the world would be transformed".  
Jesus says, "The command I give you is this, that you love one another." John 15:17