What is Emotion?

I was/am really surprised how much a single word 'Emotion' affects our whole life. For me this work on very biased manner. Some time I feel that I'm emotional person and some time not. Even till college life I never feel that I have to think a whole day on this single word. What is this, how some of us are very emotional some or not or we can say that every body has emotion because we are human being. Even all animals show their emotion.
If we go by definition of emotional person, you will find lots of definition one of them is: A person subject to strong states of emotion. Is emotion a state of feeling? Is emotion part of behavior? Is it related with heredity things?
Let’s give me some example: I was in Ballia( Town) for study and suddenly realize that I should do engineering and decide to move to Kolkata. My friend/Roommate who never talked to me like other friends ( I'll miss you, I'll feel bad if you will not be here ..etc), but I came to know that he was crying when I left for Kolkata and He watch a movie whole day in Theater. Was he emotional person? If yes then why he didn't get hurt by my word which I used for him (One example: We used to cook food at our own and responsibilities are distributed. I used to cook in very simple manner and mainly in night. When we start our dinner he started saying "Prepare Salad please, I can't eat like this. I used to say "Yes boss, you are this, you are that, your family this, now shut-up and eat what is their in plate". He never minded these words. We never seem to be closed that much but he showed his emotion once I left).
How you handle your emotion it’s totally depend upon you. People cry when they find themselves in tensed situation, nerve system start behaving in the way it should not. Strange thing is that why our emotion is not behaves in unbiased manner.
I tried to map the think but I didn't find solution. Why I didn't cry for my family when I left home for study but cried a lot for one of my friend. I tried to Google a lot but nothing was able to solve my confusion.
One thing I realized that all of us use emotional display to interact with each other. Even dog and Cow used to show their emotion to interact with us. Emotion can be positive or negative. When we started shouting on others that one is also emotion with high negative intensity: P.
I think all of us feel this emotion only because of our unconscious perception/thoughts, our surrounding.
Some time I feel that we all have something like Sensitivity system type of thing. If people are more sensitive they got hurt easily and feel harassed emotionally than the people who are less sensitive.
We can easily say that this sensitivity comes from our social nervous system.There is another problem with us (Man) that we think” if I shall express my feeling, people will think that I'm weak and it looks like weakness". Is it the case? I heard with lots of guy that "Ladka banke paida huwa hoon ro bhee nahi sakte". A man can also express their feeling. If you express your emotion you will fell very relax, you will feel like you have removed a 1000 kg wait from your head. I agree that Man has very tough time to express their feeling. So expressing your feelings is nothing but releasing pressure from you head. Else now a days I used to heard lots of disease because of keeping your feelings inside your heart, even High BPs is also one of them. Please don't hesitate to express your emotion and feelings. I come across below line in one of orkut profile 'Don't mind tears, once it will dry you will feel better'
Expressing feeling is nothing but accepting fact and taking responsibilities of your won feeling. Now after writing above line I confused again, is there any large difference in feeling and emotion?
Result is yes, feeling is what we feel, we know how it happened on another hand Emotion is something like deeper experience, emotion affects all of our system. Emotion is like a main switch once you will emotionally down, it’s going to affect all your feelings. So The Boss is our emotion. But when it comes to affect feeling is faster than emotion, for example once you will touch the fire, you will feel the heat (There is no time to think).Do you every try to think life without feeling and emotion? Just think you will find, if you don't have emotion and feeling than you are nothing but a m/c which works as instructed. Operating system was loaded in m/w when you born and it behaves the way its designed in Operating system. Some time I felt that our society is also responsible to produce such kind thing called emotion, like hiding your feelings because of society fear. A simple example, some thing bad happened with you (that means it’s a feeling) and you are feeling Sad but you are not sharing these to anybody or not crying as you learned from society that if you will cry that means you are weaker person. This small accident will be dumped in you mind for ever and if it’s a bigger accident then later it will convert into Depression. So why not we shared our initial feeling and don't let our feelings to convert into something called emotion. See the blow note copy from web:
Whether we like it or not, we are emotionally connected to virtually everyone we encounter. Our only choice is to make the connection positive or negative, to put out compassion or download resentment, to clean up emotional pollution, or contribute to it.