How to Define Love

Sad to say but my 9-5 job is boring. Nowadays though if you complain about your job, what you hear back is a very unsympathetic, "Be thankful you have a job in this economy." And yes it pays the bills, so really I am grateful for having it. Anyway, I was doing a mindless project at my place of work this morning, and I started thinking about random concepts. As in, "What is love?' Really. Try and define it. It's a brain twister.
I will put it this way, love cannot be put in a box and given away. You cannot see it with the naked eye. You cannot use your hands and grab it. You can only feel it emotionally. So it's a puzzle.
So what is it? Here's an example. My boyfriend loves me. So he sends it my way via touch, expressions, communication. I then have to make the choice to accept it.

What I think happens next is I take all of that inward, and I process it as love. So I am creating the love internally. I am creating my own feeling of being loved. He cannot create it for me. I create the whole falling in love feelings and my body chemistry reacts accordingly.
Dopamine, serotonin, oxytocin, and endorphins are released. Hormones like testosterone, and estrogen also play a role. It appears to be our brain which decides and entices us to fall in love and not our heart.
So what about the ones who fall in love with people who don't love them back? How are they able to create that feeling inside with no energy from the person they are focused on?
Are we humans so complex that we can create love all on our own? Yes, seems to be so. Even though sometimes the love is not returned.
But there is something more to all this too. Why do we choose to fall in love with some, but not others? If others are giving us the same attention, both verbally and physically, how do we not fall in love with them too. Do we sense something about them that we relate to differently?
I guess when you look closely at all emotions, we ourselves create them. Whether its subconsciously or not, we choose to internalize all, and thus create the emotion we feel is necessary. Jealousy, hate, anger, fear, we do them all.
It makes me realize just how much power we humans really have. We are creating emotions, feelings, all the time. Just the realization of this, has me now aware of just how much we really can control.
But in the end, I don't know if we will ever understand what exactly ignites that spark of love in our brain, and how that sparkle can lead us to our soul.