Love is just a feeling of very strong attachment and caring...
Like for your parents, your dog, and not to forget for ya keyboard collection :3
Love is irrational belief. Similar to the concept of God and Faith in God.
This is ok, as long as you don't fight wars over it. 
I see it more like a biological function, a result of evolution ... The attachment/caring kind of love (family members, friends) results in the formation of communities and friendships, caring / protecting / assisting each other, good for survival. The "having a crush on someone" and "sexual attraction" kind of love directly amps reproduction, it also makes the male stay / support / protect the woman until the child is born and old enough to survive alone. A lot of this behavior can be seen in the animal world as well, it's just that we gave it a name. Faith in God has nothing to do with it imo, it's just a result of "indoctrination" and humans desire to find or think up explanations for the things they don't understand, but it doesn't serve much purpose in the evolutionary POV, but highly religious people don't believe in evolution anyway, eh?
