Love is a combination of endorphins, oxytocin, and serotonin in the brain. It makes us feel good. It also helped us survive as a species, since it caused us to reproduce and protect our offspring and mates. We're biologically predisposed to love others. If you want to call that "God," so be it, or you can just call it nature.
We're also biologically predisposed to be suspicious of those who are not like us, since they could attack and kill us. It's all about survival of the species. We have to learn to love those who aren't like us, and many aren't willing to do that.
A change of thinking about the nature of love can be very useful.
We cannot command people to love us but each of us can decide to love, or not to love.
Think of love as a verb, an action word rather than a feeling. Feelings come and are not really under our control. They are, as Irwin has stated, autonomous reactions to outside stimuli.
That is one kind of love but there is another kind - unconditional love. Unconditional love is enduring and involves a certain amount of sacrifice and empathy. It is not automatic and requires a decision on our part.
An example that I have often used is the night my husband arrived home very drunk and went straight to bed. Not long after that he felt sick but was too legless to get out of bed and he vomited on the carpet next to the bed.
At that time I did not experience loving feelings towards him at all. I felt disgust but I thought for a minute and got stuck in cleaning up the mess. That was something that needed to be done and was not really praiseworthy. However, next morning I did not abuse him although I did think he deserved a few harsh words. Caring for him without rebuke was a decision I made. It was love as an action.
Today I continue to practise unconditional love as much as possible. My daughter and her husband are separated because my son in law broke his marriage vows. I continue to acknowledge him as a son and have not excluded him from the family. They may not be able to remain married but there is no reason for me to punish either of them. Both remain in my love.
When people hurt us badly, as a number of people have attested, it may not be possible to always respond with love. It may never be possible. However, when we come to the point where forgiveness seems possible we have a decision to make. We can continue to hold on to our hurt and resentment. The better decision would be to find some way to lay down the heavy emotional baggage and move forward without it. It's not easy to do but once done we are free to love ourselves and to absorb the love we do receive from others.
Love does make a difference. That is why mothers comfort little children with hugs and kisses. "Let me kiss it better", is love as an action. Love as a verb.