Because there is love, joy, and tolerance as well.  People only like to focus on the negative.   To have black, you must have white. You would not understand law if there was no chaos.   Hate, anger, fear, sadness, they are just one side of the emotional coin.  Television itself reflects what people want to see, and Violence is what people enjoy watching.  

The other reason is that by nature we are a WAR species.  We have always been happy to argue, yell, beat, and kill each other.  Hell we probably will always be such.   The fact people make little things like Skin and place of origin  such issues is further proof of the fact.  I suppose the real reason I'm as peaceful as I am, is like that of an herbivore.   If people want me dead, then I'm gonna die, why waste my time getting myself hurt when I can just sit and chill underneath the tree?   so while hate and anger are as loud as they are, that is only because they have the most real impact.  We have just as much love and happiness.   However a hug and a kiss are not as loud as a scream and a gun shot.
Love and tolerate.

Why yes... I did just use a term used by the fans of My little pony.  

WE SEE IT EVERYDAY ON TV AND HEAR ABOUT IT ALL THE TIME. I CANT UNDERSTAND WHY WE DO THE THINGS WE DO SOMETIMES, BUT I DO AGREE WITH EVERYONE ABOUT THE FAMILY THING. IT HAS TO START SOMEWHERE AND USUALLY IT BEGINS AT HOME WHEN YOU ARE LITTLE. YOU SEE OR ARE TRAINED TO DO SOMETHING A CERTAIN WAY, AND THAT'S WHAT MAKES IT SEEM OK TO DO ALL THE TIME. AND IF YOU ARE A JERK ABOUT SOMETHING, MOST PPL WILL DENY CONFRONTATION.

I don't have much to say about it in general or any real reason why it happens. Everyone has a different reason to do such things, good or bad, its what they do. No matter how much we try to stop it, its still going to be there forever.

A very good question. And I have no answer to your question. I wish i did. I would like to know the official answer as much as you want to know it.

I guess there's several contributing factors. For one, there's a lot of aggressive behavior towards one another. Many people (especially in this generation) do mean things to hurt one another. There's also peer pressure out there. The main ones that I believe,  would just about mainly be from others such as parents mistreating; often times they misdirect their hatred toward everything else.

Well, on my opinion these are the reasons for so much and hate.
1st: We are living the apocalypse, I remember something on the bible saying that the father would be against son and son be against father, nation against nation, this is something that was destined by God to happen on the Earth, and nobody can change this AND it's actually happening! I already had seen cases on the TV about a father that killed his own family and then commit suicide, and another case that a grandchild (If I remember right) KILLED his grandmother for not LOWERING THE VOLUME OF THE TV! .
2nd: People lack something important to change the world: Love.
If everybody treated everybody with love, the world would not be so much bad as it is, people would know to respect each other the way they are, people discriminates people from being different, they attack, hurt, and even kill different people.
People think that people having a different sexual orientation, is something that if they come in contact, they get affected by it, like a virus.
I think that if a person have it own way to be, it must be respected, nobody is identical to the other, NEVER.
And 3rd: People judge people by appearances and tell things that we supposedly must not do; If I go to any public place dressed in pink, am I a homosexual or something? No. If I walk around with someone that uses drugs, do I use drugs? No. People developed the common sense, which they say that someone is always in a determined way, without further research, someone can only be called the determined thing, if it is proved that the person, for example, uses drugs.
Things we supposedly must not do; Does man really not cry? Wrong. Man DOES cry, everybody cries, just because a man cries, doesn't mean that the man is not a man, everybody have the right to express their feelings.

On my opinion, these are the reasons there is so much hate and anger on the world, if some of these things change a bit, the world would  could be a better place.

Yeah, I don't get it either, we fight over pointless things don't we? Ah I guess humans were meant to be buttholes, i don't know though. I'd say it has a lot to do with 'what country has the most power' because humans believe in survival of the fittest.

Hate and anger are very vital to our existence. Think about it this way:

You are a man /woman with a family of small children and some guy breaks into your house. Now if there was no anger/hate, because you would hate this stranger coming into your home, you wouldn't have enough gumption to drive him off. 

Anger/hate is a very necessary emotion to life.

warmaker :

We are a war like species. All through history we have been a strange paradox.  Both working to survive, yet exterminate everyone else.  Hate and anger are part of who we are as a people.  Hell I actually get teased at work for being more pacifistic than others.  I am seen as strange because I do not lash out at the things that scare me. 
"Yes I'm scared of the bee, but that's not its fault.  I do not have the right to end the life of another being just because I have a problem."
However not all people see things in any form of similar way.  Humanity looks at change and difference as a negative problem.  
Gays, Blacks, abortion, every single problem we have that's big in society has to do with change and moral differences.
"Oh no! Those men are in love!"
"Oh no That man doesn't follow my god!"
"Oh no! That person has a different skin color!"
We responded to each of them with negativity.

"So what if we have no legal right, we will not let you love who you want because we do not like it."
"How dare you think for yourself! I shall make you change your mind through threats and violence!"
"You are not the same as us, that makes you Below us. Worship us you lower being!"

So long as people see difference as a problem that must be solved with blood shed, then we shall always be surrounded in hatred.

Also the secondary problem is that many of us are genuinely peaceful people, its just that the angry A holes are just so dam loud about it.  No one ever listens to the meek or quiet people when someone on the box is using the megaphone. 

edit: HAHA I just noticed id already posted my thoughts in this thread before -smirk- he he sorry to repeat some of that again, I honestly had forgotten id posted here.. Till I saw the fluttershy picture and my old response XD  My bad people my bad.  

Why Anger???
Why Joy?
Why Sad?

We are human.

I would love to quote a few philosophers and poets but it is too early in the morning for that.

((((((The Short answer is... People might be angry because they might be Trapped.))))))

I think the question is about the fun stuff that keeps popping up on the news. Plus the lack of humor in on-line conversations. And the general limiting of offline social behaviors (A.k.A. talking to people face to face).

I honestly think it has allot to do with people being trapped.
In more ways than one.
There are many professionals that have documents of Prison Inmates and the effects of Being Trapped.

If one would Compare those documents with general society. (Particularly the Current Society.)

I am certain a few interesting Items could come up and reveal themselves.
I have no time to actually do the work myself but that is my general opinion.

(I can not remember the quote but a famous Judge, that did some time, had an observation over this topic. Stating that one world can reflect the other in a very stimulating way. Wish I could remember his name.)
Anyway...
The Short answer is people are angry and feel Trapped.

Good Luck To All.
I'm done. Stick a fork in me.
Peace.

Because humans have emotions.
Emotions are powerful but can cause so much problem.
Hatred and anger have always exist and always will.
Wars will happen people will die. This is the story of humans.