Feelings and the reasons behind them

Love, Hate, Sadness, Anger, Frustration etc., etc., etc.,

What are these feelings and why do they happen to us ? Are we - humans - the only creatures on earth which experience them ?

I had some time to reflect about life in general today and I began to wonder..... Why do people fall in love ? As in, what makes people actually fall in love with someone ? Why is it that when you are in love, you tend to do anything and everything for the person you love ? Why is it that when this person whom you love is angry or shouts at you, you feel sad ? Why is it that when this person feels hurt, you feel hurt for him / her too ? Why is it that you ponder about them all the time when they are not around / with you ? Why do you remember every little detail of your life spent with them that you wouldn't normally remember if you had spent it with your other normal friends ? Why do you miss them when they are not with you ? What is it that makes them so special ? Why do people get attracted to each other ? What makes them inseparable ?

Of course, every single question here can be explained scientifically perhaps.... for example...I read somewhere recently

"Falling in love can induce a calming effect on the body and mind and raises levels of nerve growth factor for about a year, which helps to restore the nervous system and improves the lover’s memory".

Seriously ?? Is that why you always remember the details of the time you spent with your lover ? I also read the following somewhere (quoting)

"It's official: Love makes us crazy

For one thing, it causes serotonin levels in the brain to drop, which may lead people to obsess about their lover. (The levels of serotonin, a chemical produced by the body, are also low in people who have obsessive-compulsive disorder.) Next, it ramps up production of the stress hormone cortisol, leading to slightly higher blood pressure and possibly loss of sleep. Finally, a scientist at the University of London has found that when people look at their new loves, the neural circuits that are usually in charge of social judgment are suppressed. All in all, love kind of leaves you obsessive, stressed, and blind. And we love it."

I ask you people out there.... would you believe this ? And if this is true, then love is not unique to a particular lover, I mean, you can surely love more than one person, can't you ? Its just science. Then why on earth do we love the same person all our lives and remain faithful to him / her ? Well, I guess I dunno the answer to this one... If someone out there can help me on this, that would be great.....

More to come about feelings and the like..... c u all soon....